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Protein p38: an integral membrane protein specific for small vesicles of neurons and neuroendocrine cells
- Source :
- The Journal of Cell Biology
- Publication Year :
- 1986
- Publisher :
- Rockefeller University Press, 1986.
-
Abstract
- An intrinsic membrane protein of brain synaptic vesicles with Mr 38,000 (p38, synaptophysin) has recently been partially characterized (Jahn, R., W. Schiebler, C. Ouimet, and P. Greengard, 1985, Proc. Natl. Acad. Sci. USA, 83:4137-4141; Wiedenmann, B., and W. W. Franke, 1985, Cell, 41:1017-1028). We have now studied the presence of p38 in a variety of tissues by light and electron microscopy immunocytochemistry and by immunochemistry. Our results indicate that, within the nervous system, p38, like the neuron-specific phosphoprotein synapsin I, is present in virtually all nerve terminals and is selectively associated with small synaptic vesicles (SSVs). No p38 was detectable on large dense-core vesicles (LDCVs). p38 and synapsin I were found to be present in similar concentrations throughout the brain. Outside the nervous system, p38 was found in a variety of neuroendocrine cells, but not in any other cell type. In neuroendocrine cells p38 was localized on a pleiomorphic population of small, smooth-surfaced vesicles, which were interspersed among secretory granules and concentrated in the Golgi area, but not on the secretory granules themselves. Immunoblot analysis of endocrine tissues and cell lines revealed a band with a mobility slightly different from that of neuronal p38. This difference was attributable to a difference in glycosylation. The finding that p38, like synapsin I, is a component of SSVs of virtually all neurons, but not of LDCVs, supports the idea that SSVs and LDCVs are organelles of two distinct pathways for regulated neuronal secretion. In addition, our results indicate the presence in a variety of neuroendocrine cells of an endomembrane system, which is related to SSVs of neurons but is distinct from secretory granules.
- Subjects :
- Synapsin I
Synaptophysin
Nerve Tissue Proteins
Antigen-Antibody Complex
Synaptic vesicle
symbols.namesake
medicine
Animals
Tissue Distribution
Endomembrane system
biology
Vesicle
Antibodies, Monoclonal
Brain
Membrane Proteins
Rats, Inbred Strains
Articles
Cell Biology
Synapsin
Golgi apparatus
Synapsins
Rats
Cell biology
Microscopy, Electron
medicine.anatomical_structure
nervous system
Immunoglobulin G
Immunology
biology.protein
symbols
Cattle
Synaptic Vesicles
Neuron
Subjects
Details
- ISSN :
- 15408140 and 00219525
- Volume :
- 103
- Database :
- OpenAIRE
- Journal :
- The Journal of Cell Biology
- Accession number :
- edsair.doi.dedup.....feff61f665639030704ab07e86df7090