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Differential expression of SNAP‐25 family proteins in the mouse brain
Author(s) -
Yamamori Saori,
Itakura Makoto,
Sugaya Daichi,
Katsumata Osamu,
Sakagami Hiroyuki,
Takahashi Masami
Publication year - 2011
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.22558
Subject(s) - snap , biology , microbiology and biotechnology , cytoplasm , neuroscience , computer science , computer graphics (images)
Soluble N‐ethylmaleimide‐sensitive factor attachment protein (SNAP)‐25 is a neuronal SNARE protein essential for neurotransmitter release from presynaptic terminals. Three palmitoylated SNAP‐25 family proteins: SNAP‐25a, SNAP‐25b, and SNAP‐23, are expressed in the brain, but little is known about their distributions and functions. In the present study, we generated specific antibodies to distinguish these three homologous proteins. Immunoblot and immunohistochemical analyses revealed that SNAP‐25b was distributed in synapse‐enriched regions throughout almost the entire brain, whereas SNAP‐25a and SNAP‐23 were expressed in relatively specific brain regions with partially complementary expression patterns. SNAP‐25a and SNAP‐25b, but not SNAP‐23, were also present in the axoplasm of nerve fibers. The intracellular localization was also different, and although SNAP‐25b and SNAP‐23 were found primarily in membrane and lipid raft‐enriched fractions of mouse brain homogenates, a substantial amount of SNAP‐25a was recovered in soluble fractions. In PC12 cells, SNAP‐25b was localized to the plasma membrane, but SNAP‐25a and SNAP‐23 were distributed throughout the cytoplasm. The expression and distribution of these three proteins were also differentially regulated in the early postnatal period. These results indicate that the three SNAP‐25 family proteins display a differential distribution in the brain as well as in neuronal cells, and possibly play distinct roles. J. Comp. Neurol. 519:916–932, 2011. © 2010 Wiley‐Liss, Inc.