Differential distribution of synaptotagmin-1, -4, -7, and -9 in rat adrenal chromaffin cells

Hidetada Matsuoka, Keita Harada, Jun Nakamura, Mitsunori Fukuda, Masumi Inoue

    Research output: Contribution to journalArticle

    9 Citations (Scopus)

    Abstract

    Neurons and certain kinds of endocrine cells, such as adrenal chromaffin cells, have large dense-core vesicles (LDCVs) and synaptic vesicles or synaptic-like microvesicles (SLMVs). These secretory vesicles exhibit differences in Ca2+ sensitivity and contain diverse signaling substances. The present work was undertaken to identify the synaptotagmin (Syt) isoforms present in secretory vesicles. Fractionation analysis of lysates of the bovine adrenal medulla and immunocytochemistry in rat chromaffin cells indicated that Syt 1 was localized in LDCVs and SLMVs, whereas Syt 7 was the predominant isoform present in LDCVs. In contrast to PC12 cells and the pancreatic β cell line INS-1, Syt 9 was not immunodetected in LDCVs in rat chromaffin cells. Double-staining revealed that Syt 9-like immunoreactivity was nearly identical with fluorescent thapsigargin binding, suggesting the presence of Syt 9 in the endoplasmic reticulum (ER).The exogenous expression of Syt 1-GFP in INS-1 cells, which had a negligible level of endogenous Syt 1, resulted in an increase in the amount of Syt 9 in the ER, suggesting that Syt 9 competes with Syt 1 for trafficking from the ER to the Golgi complex. We conclude that LDCVs mainly contain Syt 7, whereas SLMVs contain Syt 1, but not Syt 7, in rat and bovine chromaffin cells.

    Original languageEnglish
    Pages (from-to)41-50
    Number of pages10
    JournalCell and Tissue Research
    Volume344
    Issue number1
    DOIs
    Publication statusPublished - 2011 Apr 1

    Keywords

    • Chromaffin cell
    • Chromaffin granules
    • PC12
    • Rat (Wistar, male)
    • Synaptic-like microvesicle
    • Synaptotagmin

    ASJC Scopus subject areas

    • Pathology and Forensic Medicine
    • Histology
    • Cell Biology

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