Tissue Distribution of Ca²⁺-dependent Activator Protein for Secretion Family Members CAPS1 and CAPS2 in Mice

Abstract

The family of Ca2+-dependent activator proteins for secretion (CAPS) is involved in dense-core vesicle exocytosis. CAPS1/CADPS1 and CAPS2/CADPS2 have been identified in mammals. CAPS1 regulates catecholamine release from neuroendocrine cells, whereas CAPS2 is involved in the release of brain-derived neurotrophic factor and neurotrophin-3 from cerebellar granule cells. CAPS1 and CAPS2 are predominantly expressed in brain. Here we show the immunohistochemical localization of the CAPS family proteins in various mouse tissues. In the pituitary gland, CAPS1 and CAPS2 were localized to the pars nervosa and the pars intermedia, respectively. In non-neural tissues, CAPS1 was observed in the islets of Langerhans, minor cell types of the spleen and stomach, and medullary cells of the adrenal gland, whereas CAPS2 was present in bronchial epithelial cells, thyroid parafollicular cells, chief cells of the stomach, ductal epithelium of the salivary gland, kidney proximal tubules, and minor cell types of the thymus, spleen, and colon. These results suggest that secretion from distinct cell types in various tissues involves either or both members of the CAPS family.

Uncovering Molecular Biomarkers That Correlate Cognitive Decline with the Changes of Hippocampus' Gene Expression Profiles in Alzheimer's Disease

“…We have identified 42 probes that can be divided into two groups, those that seem to be increasingly downregulated with AD severity (CABP1 [235], [236], [237], [238], [239], [240], [241], [242], [243], CADPS2 [244], [245], [246], [247], [248], [249], COLQ [250], DMD [251], [252], [253], [254], [255], [256], ELOVL2 [257], FAIM2/LFG [258], [259], [260], [261], GABBR2 [262], [263], [264], [265], GRIA2/GLUR2 [266], [267], [268], [269], [270], [271], [272], [273], [274], [275], [276], [277], ITPR1 [278], [279], [280], [281], [282], [283], KIAA0528, LZTS1/FEZ1 [284], [285], NEFM, NRG1, NRXN1, NUFIP1 [286], [287], [288], PPT1 [289], [290], [291], [292], [293], [294], [295], [296], …”

Alternative splicing variations in mouse CAPS2: differential expression and functional properties of splicing variants

“…Immunoreactive bands corresponding to short isoforms (CAPS2d-f) were observed at low to undetectable protein levels in the mouse cerebellum (Figure 5B). In addition, the previous report showed that in non-neural tissue such as pituitary, lung, pancreas and kidney, only a 150 kDa band immunoreactive for CAPS2 was detected [15]. At the mRNA level, more reaction cycles and time were needed for the amplification of transcripts encoding the short isoforms by RT-PCR and for the colorimetric detection of transcripts by in situ hybridization, respectively, indicating that the expression levels of the genes encoding the short isoforms are very low.…”

Multiple roles for the actin cytoskeleton during regulated exocytosis

“…Deletion of CAPS1 and CAPS2 in mice [134, 135] and cell cultures [136] severely impair catecholamine and glucose-stimulated-insulin release. However, the redundancy of CAPS1 and CAPS2 in tissue expression [137, 138] has not allowed researchers to precisely pinpoint their mechanism of action with the exception of the fact that both CAPS proteins bind to phosphatidylinositol 4,5-bisphosphate (PIP2), a phosphoinositide that has been shown to be required for priming [139]. Once the secretory vesicles are primed, a trigger is the only requirement to promote the fusion between the lipid bilayers of the vesicles and the plasma membrane.…”