Mark Jareb | Sacred Heart University (original) (raw)

Papers by Mark Jareb

Current Opinion in Neurobiology, Oct 1, 1992

The axonal and somatodendritic domains of neurons differ in their cytoskeletal and membrane compo... more The axonal and somatodendritic domains of neurons differ in their cytoskeletal and membrane composition, complement of organelles, and capacity for macromolecular synthesis. Recently there has been progress in elucidating the cellular mechanisms that underlie the establishment and maintenance of neuronal polarity, including microtubule organization and the sorting, transport, and anchoring of membrane proteins.

Localization, Trafficking, and Nicotine-Induced Upregulation in Clonal Mammalian Cells and in Cul... more Localization, Trafficking, and Nicotine-Induced Upregulation in Clonal Mammalian Cells and in Cultured Midbrain Neurons"

Journal of Cell Science, 1999

The 5-HT1A and 5-HT1B serotonin receptors are expressed in a variety of neurons in the central ne... more The 5-HT1A and 5-HT1B serotonin receptors are expressed in a variety of neurons in the central nervous system. While the 5-HT1A receptor is found on somas and dendrites, the 5-HT1B receptor has been suggested to be localized predominantly on axon terminals. To study the intracellular addressing of these receptors, we have used in vitro systems including Madin-Darby canine kidney (MDCK II) epithelial cells and primary neuronal cultures. Furthermore, we have extended these studies to examine addressing in vivo in transgenic mice. In epithelial cells, 5-HT1A receptors are found on both apical and basolateral membranes while 5-HT1B receptors are found exclusively in intracellular vesicles. In hippocampal neuronal cultures, 5-HT1A receptors are expressed on somatodendritic membranes but are absent from axons. In contrast, 5-HT1B receptors are found on both dendritic and axonal membranes, including growth cones where they accumulate. Using 5-HT1A and 5-HT1B knockout mice and the binary tT...

Journal of …, 2003

Fura-2 recording of Ca2+ influx was used to show that incubation in 1 microm nicotine (2-6 d) upr... more Fura-2 recording of Ca2+ influx was used to show that incubation in 1 microm nicotine (2-6 d) upregulates several pharmacological components of acetylcholine (ACh) responses in ventral midbrain cultures, including a MLA-resistant, DHbetaE-sensitive component that presumably corresponds to alpha4beta2 receptors. To study changes in alpha4beta2 receptor levels and assembly during this upregulation, we incorporated yellow and cyan fluorescent proteins (YFPs and CFPs) into the alpha4 or beta2 M3-M4 intracellular loops, and these subunits were coexpressed in human embryonic kidney (HEK) 293T cells and cultured ventral midbrain neurons. The fluorescent receptors resembled wild-type receptors in maximal responses to ACh, dose-response relations, ACh-induced Ca2+ influx, and somatic and dendritic distribution. Transfected midbrain neurons that were exposed to nicotine (1 d) displayed greater levels of fluorescent alpha4 and beta2 nicotinic ACh receptor (nAChR) subunits. As expected from the hetero-multimeric nature of alpha4beta2 receptors, coexpression of the alpha4-YFP and beta2-CFP subunits resulted in robust fluorescence resonance energy transfer (FRET), with a FRET efficiency of 22%. In midbrain neurons, dendritic alpha4beta2 nAChRs displayed greater FRET than receptors inside the soma, and in HEK293T cells, a similar increase was noted for receptors that were translocated to the surface during PKC stimulation. When cultured transfected midbrain neurons were incubated in 1 microm nicotine, there was increased FRET in the cell body, denoting increased assembly of alpha4beta2 receptors. Thus, changes in alpha4beta2 receptor assembly play a role in the regulation of alpha4beta2 levels and responses in both clonal cell lines and midbrain neurons, and the regulation may result from Ca2+-stimulated pathways.

The Journal of neuroscience : the official journal of the Society for Neuroscience, 1997

The outgrowth of neuronal processes involves a great increase in the surface area of the cell. Th... more The outgrowth of neuronal processes involves a great increase in the surface area of the cell. The supply of membrane material necessarily must be coordinated with the demands for neurite growth. The selective growth of only one or two neurites at any given time during the development of polarity raises the possibility that the production of materials by the soma is limiting for growth (Dotti and Banker, 1987; Dotti et al., Goslin and Banker, 1990). To examine the role of the availability of membrane components during the development of polarity and axonal elongation, we treated neurons with brefeldin A, an antibiotic that disrupts the trafficking of vesicles from the Golgi complex to the plasma membrane. Treatment with brefeldin A (1 microg/ml) inhibited axonal growth within 0.5 hr; in unpolarized cells it prevented the formation of an axon. These results indicate that the availability of membrane components of Golgi-derived vesicles is required for axonal growth and hence the deve...

Fura-2 recording of Ca 2 influx was used to show that incubation in 1M nicotine (2- 6 d) upregula... more Fura-2 recording of Ca 2 influx was used to show that incubation in 1M nicotine (2- 6 d) upregulates several pharmacological compo- nents of acetylcholine (ACh) responses in ventral midbrain cultures, including a MLA-resistant, DHE-sensitive component that pre- sumably corresponds to42 receptors. To study changes in42 receptor levels and assembly during this upregulation, we incorpo- rated yellow and cyan fluorescent

Proceedings of the National Academy of Sciences, 2001

Methods Reagents. We thank the following people who generously provided cDNA, virus, and͞or antib... more Methods Reagents. We thank the following people who generously provided cDNA, virus, and͞or antibodies: James Casanova, Massachusetts General Hospital, Boston, mutant polyimmunoglobulin receptor (pIgR) cDNA and pIgR sheep antisera (12);

Neuron, 1998

basolateral domain of MDCK cells, was polarized to the somatodendritic domain in cultured hippoca... more basolateral domain of MDCK cells, was polarized to the somatodendritic domain in cultured hippocampal neurons; influenza hemagglutinin (HA), which is targeted to the apical domain in MDCK cells, was polarized to the axon. Subsequent work comparing the distribution

Fura-2 recording of Ca 2ϩ influx was used to show that incubation in 1 M nicotine (2-6 d) upregul... more Fura-2 recording of Ca 2ϩ influx was used to show that incubation in 1 M nicotine (2-6 d) upregulates several pharmacological components of acetylcholine (ACh) responses in ventral midbrain cultures, including a MLA-resistant, DH␤E-sensitive component that presumably corresponds to ␣4␤2 receptors. To study changes in ␣4␤2 receptor levels and assembly during this upregulation, we incorporated yellow and cyan fluorescent proteins (YFPs and CFPs) into the ␣4 or ␤2 M3-M4 intracellular loops, and these subunits were coexpressed in human embryonic kidney (HEK) 293T cells and cultured ventral midbrain neurons. The fluorescent receptors resembled wild-type receptors in maximal responses to ACh, dose-response relations, ACh-induced Ca 2ϩ influx, and somatic and dendritic distribution. Transfected midbrain neurons that were exposed to nicotine (1 d) displayed greater levels of fluorescent ␣4 and ␤2 nicotinic ACh receptor (nAChR) subunits. As expected from the hetero-multimeric nature of ␣4␤2 receptors, coexpression of the ␣4-YFP and ␤2-CFP subunits resulted in robust fluorescence resonance energy transfer (FRET), with a FRET efficiency of 22%. In midbrain neurons, dendritic ␣4␤2 nAChRs displayed greater FRET than receptors inside the soma, and in HEK293T cells, a similar increase was noted for receptors that were translocated to the surface during PKC stimulation. When cultured transfected midbrain neurons were incubated in 1 M nicotine, there was increased FRET in the cell body, denoting increased assembly of ␣4␤2 receptors. Thus, changes in ␣4␤2 receptor assembly play a role in the regulation of ␣4␤2 levels and responses in both clonal cell lines and midbrain neurons, and the regulation may result from Ca 2ϩ-stimulated pathways.