Linghai Yang | University of Washington (original) (raw)

Papers by Linghai Yang

Biochemical and Biophysical Research Communications, 2006

Modulation on the duration of intracellular Ca 2+ transients is essential for B-cell activation. ... more Modulation on the duration of intracellular Ca 2+ transients is essential for B-cell activation. We have previously shown that extracellular-signal-regulated kinase (ERK) can phosphorylate inositol 1,4,5-trisphosphate receptor type 1 (IP 3 R1) at serine 436 and regulate its calcium channel activity. Here we investigate the potential physiological interaction between ERK and IP 3 R1 using chicken DT40 B-cell line in which different mutants are expressed. The interaction between ERK and IP 3 R1 is confirmed by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) assays. This constitutive interaction is independent of either ERK kinase activation or IP 3 R1 phosphorylation status. Back phosphorylation analysis further shows that type 1 IP 3 R (IP 3 R1) is phosphorylated by ERK in anti-IgM-activated DT40 cells. Finally, our data show that the phosphorylation of Ser 436 in the IP 3-binding domain of IP 3 R1 leads to less Ca 2+ release from endoplasmic reticulum (ER) microsomes and accelerates the declining of calcium increase in DT40 cells in response to anti-IgM stimulation.

Journal of Molecular Endocrinology, 2016

In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is us... more In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is usually elicited by binding of hormones and neurotransmitters to G protein-coupled receptors (GPCRs). cAMP exerts many of its physiological effects by activating cAMP-dependent protein kinase (PKA), which in turn phosphorylates and regulates the functions of downstream protein targets including ion channels, enzymes, and transcription factors. cAMP/PKA signaling pathway regulates glucose homeostasis at multiple levels including insulin and glucagon secretion, glucose uptake, glycogen synthesis and breakdown, gluconeogenesis, and neural control of glucose homeostasis. This review summarizes recent genetic and pharmacological studies concerning the regulation of glucose homeostasis by cAMP/PKA in pancreas, liver, skeletal muscle, adipose tissues, and brain. We also discuss the strategies for targeting cAMP/PKA pathway for research and potential therapeutic treatment of type 2 diabetes mellit...

Biochemical and Biophysical Research Communications, 2006

Calcium (Ca 2þ) release from the endoplasmic reticulum (ER) controls numerous cellular functions ... more Calcium (Ca 2þ) release from the endoplasmic reticulum (ER) controls numerous cellular functions including proliferation, and is regulated in part by inositol 1,4,5-trisphosphate receptors (IP3Rs). IP3Rs are ubiquitously expressed intracellular Ca 2þ-release channels found in many cell types. Although IP3R-mediated Ca 2þ release has been implicated in cellular proliferation, the biochemical pathways that modulate intracellular Ca 2þ release during cell cycle progression are not known. Sequence analysis of IP3R1 reveals the presence of two putative phosphorylation sites for cyclin-dependent kinases (cdks). In the present study, we show that cdc2/CyB, a critical regulator of eukaryotic cell cycle progression, phosphorylates IP3R1 in vitro and in vivo at both Ser 421 and Thr 799 and that this phosphorylation increases IP3 binding. Taken together, these results indicate that IP3R1 may be a specific target for cdc2/CyB during cell cycle progression.

Nature Communications, 2015

Mice lacking the RIIb regulatory subunit of cyclic AMP-dependent protein kinase A (PKA) display r... more Mice lacking the RIIb regulatory subunit of cyclic AMP-dependent protein kinase A (PKA) display reduced adiposity and resistance to diet-induced obesity. Here we show that RIIb knockout (KO) mice have enhanced sensitivity to leptin's effects on both feeding and energy metabolism. After administration of a low dose of leptin, the duration of hypothalamic JAK/STAT3 signalling is increased, resulting in enhanced POMC mRNA induction. Consistent with the extended JAK/STAT3 activation, we find that the negative feedback regulator of leptin receptor signalling, Socs3, is inhibited in the hypothalamus of RIIb KO mice. During fasting, RIIb-PKA is activated and this correlates with an increase in CREB phosphorylation. The increase in CREB phosphorylation is absent in the fasted RIIb KO hypothalamus. Selective inhibition of PKA activity in AgRP neurons partially recapitulates the leanness and resistance to diet-induced obesity of RIIb KO mice. Our findings suggest that RIIb-PKA modulates the duration of leptin receptor signalling and therefore the magnitude of the catabolic response to leptin.

PLOS One, 2010

AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that... more AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that is highly expressed in neurons and targets a variety of signaling molecules to dendritic membranes. AKAP5 interacts with PKA holoenzymes containing RIIa or RIIb as well as calcineurin (PP2B), PKC, calmodulin, adenylyl cyclase type V/VI, L-type calcium channels, and b-adrenergic receptors. AKAP5 has also been shown to interact with members of the MAGUK family of PSD-scaffolding proteins including PSD95 and SAP97 and target signaling molecules to receptors and ion channels in the postsynaptic density (PSD). We created two lines of AKAP5 mutant mice: a knockout of AKAP5 (KO) and a mutant that lacks the PKA binding domain of AKAP5 (D36). We find that PKA is delocalized in both the hippocampus and striatum of KO and D36 mice indicating that other neural AKAPs cannot compensate for the loss of PKA binding to AKAP5. In AKAP5 mutant mice, a significant fraction of PKA becomes localized to dendritic shafts and this correlates with increased binding to microtubule associated protein-2 (MAP2). Electrophysiological and behavioral analysis demonstrated more severe deficits in both synaptic plasticity and operant learning in the D36 mice compared with the complete KO animals. Our results indicate that the targeting of calcineurin or other binding partners of AKAP5 in the absence of the balancing kinase, PKA, leads to a disruption of synaptic plasticity and results in learning and memory defects.

Proceedings of The National Academy of Sciences, 2008

Agouti lethal yellow (Ay) mice express agouti ectopically because of a genetic rearrangement at t... more Agouti lethal yellow (Ay) mice express agouti ectopically because of a genetic rearrangement at the agouti locus. The agouti peptide is a potent antagonist of the melanocortin 4 receptor (MC4R) expressed in neurons, and this leads to hyperphagia, hypoactivity, and increased fat mass. The MC4R signals through Gs and is thought to stimulate the production of cAMP and activation of downstream cAMP effector molecules such as PKA. Disruption of the RIIβ regulatory subunit gene of PKA results in release of the active catalytic subunit and an increase in basal PKA activity in cells where RIIβ is highly expressed. Because RIIβ is expressed in neurons including those in the hypothalamic nuclei where MC4R is prominent we tested the possibility that the RIIβ knockout might rescue the body weight phenotypes of the Ay mice. Disruption of the RIIβ PKA regulatory subunit gene in mice leads to a 50% reduction in white adipose tissue and resistance to diet-induced obesity and hyperglycemia. The RIIβ mutation rescued the elevated body weight, hyperphagia, and obesity of Ay mice. Partial rescue of the Ay phenotypes was even observed on an RIIβ heterozygote background. These results suggest that the RIIβ gene mutation alters adiposity and locomotor activity by modifying PKA signaling pathways downstream of the agouti antagonism of MC4R in the hypothalamus.

PLOS One, 2010

AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that... more AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that is highly expressed in neurons and targets a variety of signaling molecules to dendritic membranes. AKAP5 interacts with PKA holoenzymes containing RIIa or RIIb as well as calcineurin (PP2B), PKC, calmodulin, adenylyl cyclase type V/VI, L-type calcium channels, and b-adrenergic receptors. AKAP5 has also been shown to interact with members of the MAGUK family of PSD-scaffolding proteins including PSD95 and SAP97 and target signaling molecules to receptors and ion channels in the postsynaptic density (PSD). We created two lines of AKAP5 mutant mice: a knockout of AKAP5 (KO) and a mutant that lacks the PKA binding domain of AKAP5 (D36). We find that PKA is delocalized in both the hippocampus and striatum of KO and D36 mice indicating that other neural AKAPs cannot compensate for the loss of PKA binding to AKAP5. In AKAP5 mutant mice, a significant fraction of PKA becomes localized to dendritic shafts and this correlates with increased binding to microtubule associated protein-2 (MAP2). Electrophysiological and behavioral analysis demonstrated more severe deficits in both synaptic plasticity and operant learning in the D36 mice compared with the complete KO animals. Our results indicate that the targeting of calcineurin or other binding partners of AKAP5 in the absence of the balancing kinase, PKA, leads to a disruption of synaptic plasticity and results in learning and memory defects.

G-protein-coupled receptors sense extracellular chemical or physical stimuli and transmit these s... more G-protein-coupled receptors sense extracellular chemical or physical stimuli and transmit these signals to distinct trimeric G-proteins. Activated G α -proteins route signals to interconnected effector cascades, thus regulating thresholds, amplitudes and durations of signalling. G α s-or G α i-coupled receptor cascades are mechanistically conserved and mediate many sensory processes, including synaptic transmission, cell proliferation and chemotaxis. Here we show that a central, conserved component of G α s-coupled receptor cascades, the regulatory subunit type-II (RII) of protein kinase A undergoes adenosine 3 ′ -5 ′ -cyclic monophosphate (cAMP)dependent binding to G α i. Stimulation of a mammalian G α i-coupled receptor and concomitant cAMP-RII binding to G α i, augments the sensitivity, amplitude and duration of G α i: β γ activity and downstream mitogen-activated protein kinase signalling, independent of protein kinase A kinase activity. The mechanism is conserved in budding yeast, causing nutrient-dependent modulation of a pheromone response. These fi ndings suggest a direct mechanism by which coincident activation of G α s-coupled receptors controls the precision of adaptive responses of activated G α i-coupled receptor cascades.

Biochemical and Biophysical Research Communications, 2006

Modulation on the duration of intracellular Ca 2+ transients is essential for B-cell activation. ... more Modulation on the duration of intracellular Ca 2+ transients is essential for B-cell activation. We have previously shown that extracellular-signal-regulated kinase (ERK) can phosphorylate inositol 1,4,5-trisphosphate receptor type 1 (IP 3 R1) at serine 436 and regulate its calcium channel activity. Here we investigate the potential physiological interaction between ERK and IP 3 R1 using chicken DT40 B-cell line in which different mutants are expressed. The interaction between ERK and IP 3 R1 is confirmed by co-immunoprecipitation and fluorescence resonance energy transfer (FRET) assays. This constitutive interaction is independent of either ERK kinase activation or IP 3 R1 phosphorylation status. Back phosphorylation analysis further shows that type 1 IP 3 R (IP 3 R1) is phosphorylated by ERK in anti-IgM-activated DT40 cells. Finally, our data show that the phosphorylation of Ser 436 in the IP 3-binding domain of IP 3 R1 leads to less Ca 2+ release from endoplasmic reticulum (ER) microsomes and accelerates the declining of calcium increase in DT40 cells in response to anti-IgM stimulation.

Journal of Molecular Endocrinology, 2016

In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is us... more In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is usually elicited by binding of hormones and neurotransmitters to G protein-coupled receptors (GPCRs). cAMP exerts many of its physiological effects by activating cAMP-dependent protein kinase (PKA), which in turn phosphorylates and regulates the functions of downstream protein targets including ion channels, enzymes, and transcription factors. cAMP/PKA signaling pathway regulates glucose homeostasis at multiple levels including insulin and glucagon secretion, glucose uptake, glycogen synthesis and breakdown, gluconeogenesis, and neural control of glucose homeostasis. This review summarizes recent genetic and pharmacological studies concerning the regulation of glucose homeostasis by cAMP/PKA in pancreas, liver, skeletal muscle, adipose tissues, and brain. We also discuss the strategies for targeting cAMP/PKA pathway for research and potential therapeutic treatment of type 2 diabetes mellit...

Biochemical and Biophysical Research Communications, 2006

Calcium (Ca 2þ) release from the endoplasmic reticulum (ER) controls numerous cellular functions ... more Calcium (Ca 2þ) release from the endoplasmic reticulum (ER) controls numerous cellular functions including proliferation, and is regulated in part by inositol 1,4,5-trisphosphate receptors (IP3Rs). IP3Rs are ubiquitously expressed intracellular Ca 2þ-release channels found in many cell types. Although IP3R-mediated Ca 2þ release has been implicated in cellular proliferation, the biochemical pathways that modulate intracellular Ca 2þ release during cell cycle progression are not known. Sequence analysis of IP3R1 reveals the presence of two putative phosphorylation sites for cyclin-dependent kinases (cdks). In the present study, we show that cdc2/CyB, a critical regulator of eukaryotic cell cycle progression, phosphorylates IP3R1 in vitro and in vivo at both Ser 421 and Thr 799 and that this phosphorylation increases IP3 binding. Taken together, these results indicate that IP3R1 may be a specific target for cdc2/CyB during cell cycle progression.

Nature Communications, 2015

Mice lacking the RIIb regulatory subunit of cyclic AMP-dependent protein kinase A (PKA) display r... more Mice lacking the RIIb regulatory subunit of cyclic AMP-dependent protein kinase A (PKA) display reduced adiposity and resistance to diet-induced obesity. Here we show that RIIb knockout (KO) mice have enhanced sensitivity to leptin's effects on both feeding and energy metabolism. After administration of a low dose of leptin, the duration of hypothalamic JAK/STAT3 signalling is increased, resulting in enhanced POMC mRNA induction. Consistent with the extended JAK/STAT3 activation, we find that the negative feedback regulator of leptin receptor signalling, Socs3, is inhibited in the hypothalamus of RIIb KO mice. During fasting, RIIb-PKA is activated and this correlates with an increase in CREB phosphorylation. The increase in CREB phosphorylation is absent in the fasted RIIb KO hypothalamus. Selective inhibition of PKA activity in AgRP neurons partially recapitulates the leanness and resistance to diet-induced obesity of RIIb KO mice. Our findings suggest that RIIb-PKA modulates the duration of leptin receptor signalling and therefore the magnitude of the catabolic response to leptin.

PLOS One, 2010

AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that... more AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that is highly expressed in neurons and targets a variety of signaling molecules to dendritic membranes. AKAP5 interacts with PKA holoenzymes containing RIIa or RIIb as well as calcineurin (PP2B), PKC, calmodulin, adenylyl cyclase type V/VI, L-type calcium channels, and b-adrenergic receptors. AKAP5 has also been shown to interact with members of the MAGUK family of PSD-scaffolding proteins including PSD95 and SAP97 and target signaling molecules to receptors and ion channels in the postsynaptic density (PSD). We created two lines of AKAP5 mutant mice: a knockout of AKAP5 (KO) and a mutant that lacks the PKA binding domain of AKAP5 (D36). We find that PKA is delocalized in both the hippocampus and striatum of KO and D36 mice indicating that other neural AKAPs cannot compensate for the loss of PKA binding to AKAP5. In AKAP5 mutant mice, a significant fraction of PKA becomes localized to dendritic shafts and this correlates with increased binding to microtubule associated protein-2 (MAP2). Electrophysiological and behavioral analysis demonstrated more severe deficits in both synaptic plasticity and operant learning in the D36 mice compared with the complete KO animals. Our results indicate that the targeting of calcineurin or other binding partners of AKAP5 in the absence of the balancing kinase, PKA, leads to a disruption of synaptic plasticity and results in learning and memory defects.

Proceedings of The National Academy of Sciences, 2008

Agouti lethal yellow (Ay) mice express agouti ectopically because of a genetic rearrangement at t... more Agouti lethal yellow (Ay) mice express agouti ectopically because of a genetic rearrangement at the agouti locus. The agouti peptide is a potent antagonist of the melanocortin 4 receptor (MC4R) expressed in neurons, and this leads to hyperphagia, hypoactivity, and increased fat mass. The MC4R signals through Gs and is thought to stimulate the production of cAMP and activation of downstream cAMP effector molecules such as PKA. Disruption of the RIIβ regulatory subunit gene of PKA results in release of the active catalytic subunit and an increase in basal PKA activity in cells where RIIβ is highly expressed. Because RIIβ is expressed in neurons including those in the hypothalamic nuclei where MC4R is prominent we tested the possibility that the RIIβ knockout might rescue the body weight phenotypes of the Ay mice. Disruption of the RIIβ PKA regulatory subunit gene in mice leads to a 50% reduction in white adipose tissue and resistance to diet-induced obesity and hyperglycemia. The RIIβ mutation rescued the elevated body weight, hyperphagia, and obesity of Ay mice. Partial rescue of the Ay phenotypes was even observed on an RIIβ heterozygote background. These results suggest that the RIIβ gene mutation alters adiposity and locomotor activity by modifying PKA signaling pathways downstream of the agouti antagonism of MC4R in the hypothalamus.

PLOS One, 2010

AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that... more AKAP5 (also referred to as AKAP150 in rodents and AKAP79 in humans) is a scaffolding protein that is highly expressed in neurons and targets a variety of signaling molecules to dendritic membranes. AKAP5 interacts with PKA holoenzymes containing RIIa or RIIb as well as calcineurin (PP2B), PKC, calmodulin, adenylyl cyclase type V/VI, L-type calcium channels, and b-adrenergic receptors. AKAP5 has also been shown to interact with members of the MAGUK family of PSD-scaffolding proteins including PSD95 and SAP97 and target signaling molecules to receptors and ion channels in the postsynaptic density (PSD). We created two lines of AKAP5 mutant mice: a knockout of AKAP5 (KO) and a mutant that lacks the PKA binding domain of AKAP5 (D36). We find that PKA is delocalized in both the hippocampus and striatum of KO and D36 mice indicating that other neural AKAPs cannot compensate for the loss of PKA binding to AKAP5. In AKAP5 mutant mice, a significant fraction of PKA becomes localized to dendritic shafts and this correlates with increased binding to microtubule associated protein-2 (MAP2). Electrophysiological and behavioral analysis demonstrated more severe deficits in both synaptic plasticity and operant learning in the D36 mice compared with the complete KO animals. Our results indicate that the targeting of calcineurin or other binding partners of AKAP5 in the absence of the balancing kinase, PKA, leads to a disruption of synaptic plasticity and results in learning and memory defects.

G-protein-coupled receptors sense extracellular chemical or physical stimuli and transmit these s... more G-protein-coupled receptors sense extracellular chemical or physical stimuli and transmit these signals to distinct trimeric G-proteins. Activated G α -proteins route signals to interconnected effector cascades, thus regulating thresholds, amplitudes and durations of signalling. G α s-or G α i-coupled receptor cascades are mechanistically conserved and mediate many sensory processes, including synaptic transmission, cell proliferation and chemotaxis. Here we show that a central, conserved component of G α s-coupled receptor cascades, the regulatory subunit type-II (RII) of protein kinase A undergoes adenosine 3 ′ -5 ′ -cyclic monophosphate (cAMP)dependent binding to G α i. Stimulation of a mammalian G α i-coupled receptor and concomitant cAMP-RII binding to G α i, augments the sensitivity, amplitude and duration of G α i: β γ activity and downstream mitogen-activated protein kinase signalling, independent of protein kinase A kinase activity. The mechanism is conserved in budding yeast, causing nutrient-dependent modulation of a pheromone response. These fi ndings suggest a direct mechanism by which coincident activation of G α s-coupled receptors controls the precision of adaptive responses of activated G α i-coupled receptor cascades.