Linda Hendershot - Academia.edu (original) (raw)

Papers by Linda Hendershot

Infection and Immunity, Oct 1, 1986

After infection with a cloned population of Trypanosoma vivax, C57BL/6 mice controlled parasitemi... more After infection with a cloned population of Trypanosoma vivax, C57BL/6 mice controlled parasitemia during the exponential growth phase and survived, with intermittent parasitemia, for several weeks. In contrast, most mice of the C3H/He strain did not control the first wave of parasitemia and died within 9 to 13 days after infection. Control of parasitemia in C57BL/6 mice was mediated by the production of a variant surface glycoprotein-specific trypanodestructive antibody response which was accompanied by production of antibodies against antigens shared between procyclic and bloodstream T. vivax as well as antibodies against trinitrophenyl (TNP) and sheep erythrocytes. The infected C3HIHe mice did not produce trypanodestructive antibodies or antibodies against procyclic antigens or TNP but did produce antibodies against sheep erythrocytes. Although infected C57BL/6 mice produced levels of serum immunoglobulin M four times higher than infected C3HIHe mice, their parasite-induced B-cell DNA synthetic responses were similar, and both sets of mice developed similar numbers of spleen cells with cytoplasmic immunoglobulin M, a proportion of which could react with TNP. In vitro biosynthetic labeling studies accompanied by immunoglobulin precipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that the immunoglobulin-containing cells of infected C3H/He mice synthesized and secreted less immunoglobulin than similar cells from infected C57BL/6 mice. We concluded that some parasite-induced antibody-forming cells in C3H/He mice, perhaps including parasite-specific and certainly including TNP-specific cells, had an impaired capacity to make and release immunoglobulin. Within 24 h after Berenil-mediated elimination of T. vivax from infected C3H/He mice, a population of cyclophosphamide-sensitive spleen cells produced large amounts of parasite-specific and TNP-specific antibody. We concluded that the defect in terminal B-cell function leading to suppressed parasite-specific and TNP-specific antibody responses was induced either by living trypanosomes or short-lived factors from degenerating trypanosomes or by short-lived parasite-induced host responses.

Oxidative Folding of Proteins, 2018

Disulfide bonds are unique among post-translational modifications, as they add covalent crosslink... more Disulfide bonds are unique among post-translational modifications, as they add covalent crosslinks to the polypeptide chain. Accordingly, they can exert pronounced effects on protein folding and stability. This is of particular importance for secreted or cell surface proteins, where disulfide bonds are abundant and serve to stabilize proteins against unfolding and dissociation in the extracellular milieu. However, in addition to these bonds providing security to a natively folded protein or aiding the folding process by stabilizing folding intermediates, the cysteines that form these bonds can be perilous during the maturation of nascent polypeptide chains as they enter the endoplasmic reticulum where the concentration of unfolded proteins approaches millimolar levels. This danger is even greater if the native bonds ultimately form between non-consecutive cysteines that are distant in the linear sequence or if non-native bonds are a prerequisite to achieving the final, functional structure of a protein. A wealth of exquisite detail has been obtained from in vitro studies on the biophysical effects of disulfide bonds on protein folding. Correspondingly, in-depth in vivo studies have established that the same principles apply to oxidative folding in a cell, but reveal a much more complex folding trajectory for many of the proteins that have been examined. In this chapter, we review the biophysical properties of disulfide bonds and how they affect the structure and folding of individual proteins. Based on this, we discuss similarities and differences between in vitro and in vivo folding reactions. The types of disulfide bonds that form during co-translational protein folding are described, as are the cellular strategies for accommodating this risk-laden covalent modification. We conclude with a discussion of the impact of disulfide bonds on protein misfolding and human disease.

wrote the paper. Conflict of interest statement: A patent for optimized antibodies based on the r... more wrote the paper. Conflict of interest statement: A patent for optimized antibodies based on the results presented in this study has been filed. This article is a PNAS Direct Submission. Data deposition: The atomic coordinates have been deposited in the Protein Data Bank, www.pdb.org [PDB ID codes 4Q97 (C1), 4Q9B (C2), 4Q9C (C3), and 2MKL (C4)]. The NMR chemical shifts have been deposited in the BioMagResBank, www.bmrb.wisc.edu (accession no. 19783).

The FASEB Journal, May 1, 2022

한국생명과학회 심포지움, Apr 1, 2005

PLOS ONE, Sep 2, 2010

Background: Inadequate extracellular conditions can adversely affect the environment of the ER an... more Background: Inadequate extracellular conditions can adversely affect the environment of the ER and impinge on the maturation of nascent proteins. The resultant accumulation of unfolded proteins activates a signal transduction pathway, known as the unfolded protein response, which serves primarily to protect the cell during stress and helps restore homeostasis to the ER.

Frontier Media SA eBooks, 2023

Methods in Enzymology, 2017

Mass spectrometry-based proteomics has experienced an unprecedented advance in comprehensive anal... more Mass spectrometry-based proteomics has experienced an unprecedented advance in comprehensive analysis of proteins and posttranslational modifications, with particular technical progress in liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and isobaric labeling multiplexing capacity. Here we introduce a deep proteomics profiling protocol that combines 10-plex tandem mass tag (TMT) labeling with an optimized LC-MS/MS platform to quantitate whole proteome and phosphoproteome. The major steps include protein extraction and digestion, TMT labeling, two dimensional liquid chromatography, TiO 2-mediated phosphopeptide enrichment, high resolution mass spectrometry, and computational data processing. This protocol routinely leads to confident quantification of more than 10,000 proteins and approximately 30,000 phosphosites in mammalian samples. Quality control steps are implemented for troubleshooting and evaluating experimental variation. Such a multiplexed robust method provides a powerful tool for dissecting proteomic signatures at the systems level in a variety of complex samples, ranging from cell culture, animal tissues to human clinical specimens.

The EMBO Journal, 1992

The immunoglobulin heavy chain binding protein BiP/GRP78 is post-translationally modified by phos... more The immunoglobulin heavy chain binding protein BiP/GRP78 is post-translationally modified by phosphorylation and ADP ribosylation. In cells induced to synthesize higher levels of BiP, either due to the accumulation of nontransported proteins or to glucose starvation, both BiP phosphorylation and ADP ribosylation are reduced. BiP bound to other proteins is unmodified, suggesting that both phosphorylation and ADP ribosylation are restricted to the unbound BiP pool. In the present study, both modifications were further characterized in terms of their stability, the pool of BiP that harbored these modifications, and the relationship between the modified and unmodified forms of BiP. While levels of BiP synthesis vary according to the physiological state of a cell, we found that both induced and uninduced cells contain similar amounts of free BiP. However, free BiP in uninduced cells was found primarily in an aggregated state, whereas in cells that accumulate nontransported proteins, it was predominantly monomeric. Both phosphorylation and ADP ribosylation were restricted to the aggregated form of free BiP. These post-translational modifications occurred upon release of BiP from associated proteins, and could be reversed upon induction of BiP synthesis. Therefore, BiP exists either (1) complexed to other proteins, (2) as a free unmodified monomer, or (3) as free modified aggregates. Our data suggest that BiP can be interconverted from one state to another, and that the various forms are functionally distinct.

Molecular Cell, Apr 1, 2022

Endoplasmic reticulum quality control (ERQC) pathways comprising chaperones, folding enzymes, and... more Endoplasmic reticulum quality control (ERQC) pathways comprising chaperones, folding enzymes, and degradation factors ensure the fidelity of ER protein folding and trafficking to downstream secretory environments. However, multiple factors, including tissue-specific secretory proteomes, environmental and genetic insults, and organismal aging, challenge ERQC. Thus, a key question is: how do cells adapt ERQC to match the diverse, ever-changing demands encountered during normal physiology and in disease? The answer lies in the unfolded protein response (UPR), a signaling mechanism activated by ER stress. In mammals, the UPR comprises three signaling pathways regulated downstream of the ER membrane proteins IRE1, ATF6, and PERK. Upon activation, these UPR pathways remodel ERQC to alleviate cellular stress and restore ER function. Here, we describe how UPR signaling pathways adapt ERQC, highlighting their importance for maintaining ER function across tissues and the potential for targeting the UPR to mitigate pathologies associated with protein misfolding diseases.

Molecular and Cellular Endocrinology, 2020

Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the ... more Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the endoplasmic reticulum (ER) where they undergo post-translational modifications, oxidative folding, and subunit assembly in tightly monitored processes. An ER quality control (ERQC) system oversees protein maturation and ensures that only those reaching their native state will continue trafficking into the secretory pathway to reach their final destinations. Those that fail must be recognized and eliminated to maintain ER homeostasis. Two cellular mechanisms have been identified to rid the ER of terminally unfolded and aggregated proteins. ER-associated degradation (ERAD) was discovered nearly 30 years ago and entails the identification of improperly matured secretory pathway proteins and their retrotranslocation to the cytosol for degradation by the ubiquitin-proteasome system. ER-phagy has been more recently described and caters to larger, more complex proteins and protein aggregates that are not readily handled by ERAD. This pathway has unique upstream components and relies on the same downstream effectors of autophagy used in other cellular processes to deliver clients to lysosomes for degradation. In this review, we describe the main elements of ERQC, ERAD, and ER-phagy and focus on recent advances in these fields.

Faculty reviews, 2022

Proteins that are expressed on membrane surfaces or secreted are involved in all aspects of cellu... more Proteins that are expressed on membrane surfaces or secreted are involved in all aspects of cellular and organismal life, and as such require extremely high fidelity during their synthesis and maturation. These proteins are synthesized at the endoplasmic reticulum (ER) where a dedicated quality control system (ERQC) ensures only properly matured proteins reach their destinations. An essential component of this process is the identification of proteins that fail to pass ERQC and their retrotranslocation to the cytosol for proteasomal degradation. This study by Wu et al. reports a cryo-electron microscopy (cryo-EM) structure of the five-protein channel through which aberrant proteins are extracted from the ER, providing insights into how recognition of misfolded proteins is coupled to their transport through a hydrophobic channel that acts to thin the ER membrane, further facilitating their dislocation to the cytosol1.

Frontiers in Cell and Developmental Biology

Antibody monomers are produced from two immunoglobulin heavy chains and two light chains that are... more Antibody monomers are produced from two immunoglobulin heavy chains and two light chains that are folded and assembled in the endoplasmic reticulum This process is assisted and monitored by components of the endoplasmic reticulum quality control machinery; an outcome made more fraught by the unusual genetic machinations employed to produce a seemingly unlimited antibody repertoire. Proper functioning of the adaptive immune system is as dependent on the success of this operation, as it is on the ability to identify and degrade those molecules that fail to reach their native state. In this study, two rate-limiting steps were identified in the degradation of a non-secreted κ light chain. Both focus on the constant domain (CL), which has evolved to fold rapidly and very stably to serve as a catalyst for the folding of the heavy chain CH1 domain. The first hurdle is the reduction of the disulfide bond in the CLdomain, which is required for retrotranslocation to the cytosol. In spite of b...

Frontiers Research Topics

All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.

Molecular and Cellular Endocrinology, 2019

Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the ... more Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the endoplasmic reticulum (ER) where they undergo post-translational modifications, oxidative folding, and subunit assembly in tightly monitored processes. An ER quality control (ERQC) system oversees protein maturation and ensures that only those reaching their native state will continue trafficking into the secretory pathway to reach their final destinations. Those that fail must be recognized and eliminated to maintain ER homeostasis. Two cellular mechanisms have been identified to rid the ER of terminally unfolded and aggregated proteins. ER-associated degradation (ERAD) was discovered nearly 30 years ago and entails the identification of improperly matured secretory pathway proteins and their retrotranslocation to the cytosol for degradation by the ubiquitin-proteasome system. ER-phagy has been more recently described and caters to larger, more complex proteins and protein aggregates that are not readily handled by ERAD. This pathway has unique upstream components and relies on the same downstream effectors of autophagy used in other cellular processes to deliver clients to lysosomes for degradation. In this review, we describe the main elements of ERQC, ERAD, and ER-phagy and focus on recent advances in these fields.

Infection and Immunity, Oct 1, 1986

After infection with a cloned population of Trypanosoma vivax, C57BL/6 mice controlled parasitemi... more After infection with a cloned population of Trypanosoma vivax, C57BL/6 mice controlled parasitemia during the exponential growth phase and survived, with intermittent parasitemia, for several weeks. In contrast, most mice of the C3H/He strain did not control the first wave of parasitemia and died within 9 to 13 days after infection. Control of parasitemia in C57BL/6 mice was mediated by the production of a variant surface glycoprotein-specific trypanodestructive antibody response which was accompanied by production of antibodies against antigens shared between procyclic and bloodstream T. vivax as well as antibodies against trinitrophenyl (TNP) and sheep erythrocytes. The infected C3HIHe mice did not produce trypanodestructive antibodies or antibodies against procyclic antigens or TNP but did produce antibodies against sheep erythrocytes. Although infected C57BL/6 mice produced levels of serum immunoglobulin M four times higher than infected C3HIHe mice, their parasite-induced B-cell DNA synthetic responses were similar, and both sets of mice developed similar numbers of spleen cells with cytoplasmic immunoglobulin M, a proportion of which could react with TNP. In vitro biosynthetic labeling studies accompanied by immunoglobulin precipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that the immunoglobulin-containing cells of infected C3H/He mice synthesized and secreted less immunoglobulin than similar cells from infected C57BL/6 mice. We concluded that some parasite-induced antibody-forming cells in C3H/He mice, perhaps including parasite-specific and certainly including TNP-specific cells, had an impaired capacity to make and release immunoglobulin. Within 24 h after Berenil-mediated elimination of T. vivax from infected C3H/He mice, a population of cyclophosphamide-sensitive spleen cells produced large amounts of parasite-specific and TNP-specific antibody. We concluded that the defect in terminal B-cell function leading to suppressed parasite-specific and TNP-specific antibody responses was induced either by living trypanosomes or short-lived factors from degenerating trypanosomes or by short-lived parasite-induced host responses.

Oxidative Folding of Proteins, 2018

Disulfide bonds are unique among post-translational modifications, as they add covalent crosslink... more Disulfide bonds are unique among post-translational modifications, as they add covalent crosslinks to the polypeptide chain. Accordingly, they can exert pronounced effects on protein folding and stability. This is of particular importance for secreted or cell surface proteins, where disulfide bonds are abundant and serve to stabilize proteins against unfolding and dissociation in the extracellular milieu. However, in addition to these bonds providing security to a natively folded protein or aiding the folding process by stabilizing folding intermediates, the cysteines that form these bonds can be perilous during the maturation of nascent polypeptide chains as they enter the endoplasmic reticulum where the concentration of unfolded proteins approaches millimolar levels. This danger is even greater if the native bonds ultimately form between non-consecutive cysteines that are distant in the linear sequence or if non-native bonds are a prerequisite to achieving the final, functional structure of a protein. A wealth of exquisite detail has been obtained from in vitro studies on the biophysical effects of disulfide bonds on protein folding. Correspondingly, in-depth in vivo studies have established that the same principles apply to oxidative folding in a cell, but reveal a much more complex folding trajectory for many of the proteins that have been examined. In this chapter, we review the biophysical properties of disulfide bonds and how they affect the structure and folding of individual proteins. Based on this, we discuss similarities and differences between in vitro and in vivo folding reactions. The types of disulfide bonds that form during co-translational protein folding are described, as are the cellular strategies for accommodating this risk-laden covalent modification. We conclude with a discussion of the impact of disulfide bonds on protein misfolding and human disease.

wrote the paper. Conflict of interest statement: A patent for optimized antibodies based on the r... more wrote the paper. Conflict of interest statement: A patent for optimized antibodies based on the results presented in this study has been filed. This article is a PNAS Direct Submission. Data deposition: The atomic coordinates have been deposited in the Protein Data Bank, www.pdb.org [PDB ID codes 4Q97 (C1), 4Q9B (C2), 4Q9C (C3), and 2MKL (C4)]. The NMR chemical shifts have been deposited in the BioMagResBank, www.bmrb.wisc.edu (accession no. 19783).

The FASEB Journal, May 1, 2022

한국생명과학회 심포지움, Apr 1, 2005

PLOS ONE, Sep 2, 2010

Background: Inadequate extracellular conditions can adversely affect the environment of the ER an... more Background: Inadequate extracellular conditions can adversely affect the environment of the ER and impinge on the maturation of nascent proteins. The resultant accumulation of unfolded proteins activates a signal transduction pathway, known as the unfolded protein response, which serves primarily to protect the cell during stress and helps restore homeostasis to the ER.

Frontier Media SA eBooks, 2023

Methods in Enzymology, 2017

Mass spectrometry-based proteomics has experienced an unprecedented advance in comprehensive anal... more Mass spectrometry-based proteomics has experienced an unprecedented advance in comprehensive analysis of proteins and posttranslational modifications, with particular technical progress in liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and isobaric labeling multiplexing capacity. Here we introduce a deep proteomics profiling protocol that combines 10-plex tandem mass tag (TMT) labeling with an optimized LC-MS/MS platform to quantitate whole proteome and phosphoproteome. The major steps include protein extraction and digestion, TMT labeling, two dimensional liquid chromatography, TiO 2-mediated phosphopeptide enrichment, high resolution mass spectrometry, and computational data processing. This protocol routinely leads to confident quantification of more than 10,000 proteins and approximately 30,000 phosphosites in mammalian samples. Quality control steps are implemented for troubleshooting and evaluating experimental variation. Such a multiplexed robust method provides a powerful tool for dissecting proteomic signatures at the systems level in a variety of complex samples, ranging from cell culture, animal tissues to human clinical specimens.

The EMBO Journal, 1992

The immunoglobulin heavy chain binding protein BiP/GRP78 is post-translationally modified by phos... more The immunoglobulin heavy chain binding protein BiP/GRP78 is post-translationally modified by phosphorylation and ADP ribosylation. In cells induced to synthesize higher levels of BiP, either due to the accumulation of nontransported proteins or to glucose starvation, both BiP phosphorylation and ADP ribosylation are reduced. BiP bound to other proteins is unmodified, suggesting that both phosphorylation and ADP ribosylation are restricted to the unbound BiP pool. In the present study, both modifications were further characterized in terms of their stability, the pool of BiP that harbored these modifications, and the relationship between the modified and unmodified forms of BiP. While levels of BiP synthesis vary according to the physiological state of a cell, we found that both induced and uninduced cells contain similar amounts of free BiP. However, free BiP in uninduced cells was found primarily in an aggregated state, whereas in cells that accumulate nontransported proteins, it was predominantly monomeric. Both phosphorylation and ADP ribosylation were restricted to the aggregated form of free BiP. These post-translational modifications occurred upon release of BiP from associated proteins, and could be reversed upon induction of BiP synthesis. Therefore, BiP exists either (1) complexed to other proteins, (2) as a free unmodified monomer, or (3) as free modified aggregates. Our data suggest that BiP can be interconverted from one state to another, and that the various forms are functionally distinct.

Molecular Cell, Apr 1, 2022

Endoplasmic reticulum quality control (ERQC) pathways comprising chaperones, folding enzymes, and... more Endoplasmic reticulum quality control (ERQC) pathways comprising chaperones, folding enzymes, and degradation factors ensure the fidelity of ER protein folding and trafficking to downstream secretory environments. However, multiple factors, including tissue-specific secretory proteomes, environmental and genetic insults, and organismal aging, challenge ERQC. Thus, a key question is: how do cells adapt ERQC to match the diverse, ever-changing demands encountered during normal physiology and in disease? The answer lies in the unfolded protein response (UPR), a signaling mechanism activated by ER stress. In mammals, the UPR comprises three signaling pathways regulated downstream of the ER membrane proteins IRE1, ATF6, and PERK. Upon activation, these UPR pathways remodel ERQC to alleviate cellular stress and restore ER function. Here, we describe how UPR signaling pathways adapt ERQC, highlighting their importance for maintaining ER function across tissues and the potential for targeting the UPR to mitigate pathologies associated with protein misfolding diseases.

Molecular and Cellular Endocrinology, 2020

Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the ... more Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the endoplasmic reticulum (ER) where they undergo post-translational modifications, oxidative folding, and subunit assembly in tightly monitored processes. An ER quality control (ERQC) system oversees protein maturation and ensures that only those reaching their native state will continue trafficking into the secretory pathway to reach their final destinations. Those that fail must be recognized and eliminated to maintain ER homeostasis. Two cellular mechanisms have been identified to rid the ER of terminally unfolded and aggregated proteins. ER-associated degradation (ERAD) was discovered nearly 30 years ago and entails the identification of improperly matured secretory pathway proteins and their retrotranslocation to the cytosol for degradation by the ubiquitin-proteasome system. ER-phagy has been more recently described and caters to larger, more complex proteins and protein aggregates that are not readily handled by ERAD. This pathway has unique upstream components and relies on the same downstream effectors of autophagy used in other cellular processes to deliver clients to lysosomes for degradation. In this review, we describe the main elements of ERQC, ERAD, and ER-phagy and focus on recent advances in these fields.

Faculty reviews, 2022

Proteins that are expressed on membrane surfaces or secreted are involved in all aspects of cellu... more Proteins that are expressed on membrane surfaces or secreted are involved in all aspects of cellular and organismal life, and as such require extremely high fidelity during their synthesis and maturation. These proteins are synthesized at the endoplasmic reticulum (ER) where a dedicated quality control system (ERQC) ensures only properly matured proteins reach their destinations. An essential component of this process is the identification of proteins that fail to pass ERQC and their retrotranslocation to the cytosol for proteasomal degradation. This study by Wu et al. reports a cryo-electron microscopy (cryo-EM) structure of the five-protein channel through which aberrant proteins are extracted from the ER, providing insights into how recognition of misfolded proteins is coupled to their transport through a hydrophobic channel that acts to thin the ER membrane, further facilitating their dislocation to the cytosol1.

Frontiers in Cell and Developmental Biology

Antibody monomers are produced from two immunoglobulin heavy chains and two light chains that are... more Antibody monomers are produced from two immunoglobulin heavy chains and two light chains that are folded and assembled in the endoplasmic reticulum This process is assisted and monitored by components of the endoplasmic reticulum quality control machinery; an outcome made more fraught by the unusual genetic machinations employed to produce a seemingly unlimited antibody repertoire. Proper functioning of the adaptive immune system is as dependent on the success of this operation, as it is on the ability to identify and degrade those molecules that fail to reach their native state. In this study, two rate-limiting steps were identified in the degradation of a non-secreted κ light chain. Both focus on the constant domain (CL), which has evolved to fold rapidly and very stably to serve as a catalyst for the folding of the heavy chain CH1 domain. The first hurdle is the reduction of the disulfide bond in the CLdomain, which is required for retrotranslocation to the cytosol. In spite of b...

Frontiers Research Topics

All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.

Molecular and Cellular Endocrinology, 2019

Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the ... more Secreted, plasma membrane, and resident proteins of the secretory pathway are synthesized in the endoplasmic reticulum (ER) where they undergo post-translational modifications, oxidative folding, and subunit assembly in tightly monitored processes. An ER quality control (ERQC) system oversees protein maturation and ensures that only those reaching their native state will continue trafficking into the secretory pathway to reach their final destinations. Those that fail must be recognized and eliminated to maintain ER homeostasis. Two cellular mechanisms have been identified to rid the ER of terminally unfolded and aggregated proteins. ER-associated degradation (ERAD) was discovered nearly 30 years ago and entails the identification of improperly matured secretory pathway proteins and their retrotranslocation to the cytosol for degradation by the ubiquitin-proteasome system. ER-phagy has been more recently described and caters to larger, more complex proteins and protein aggregates that are not readily handled by ERAD. This pathway has unique upstream components and relies on the same downstream effectors of autophagy used in other cellular processes to deliver clients to lysosomes for degradation. In this review, we describe the main elements of ERQC, ERAD, and ER-phagy and focus on recent advances in these fields.