Sec15 protein, an essential component of the exocytotic apparatis, is associated with the plasma membrane and with a soluble 19.5S particle

Document Type

Article

Abstract

SEC15 encodes a 116-kD protein that is essential for vesicular traffic from the Golgi apparatus to the cell surface in yeast. Although the sequence predicts a largely hydrophilic protein, a portion (23%) of Sec15p is found in association with the plasma membrane. The remainder is not associated with a membrane but is found in a 19.5S particle which is not dissociated by 0.5 M NaCl. Sec15p may attach directly to the plasma membrane since it is not found on the Golgi apparatus nor on the secretory vesicle precursors to the plasma membrane. Loss of function of most of the late-acting sec gene products does not alter the distribution of Sec15p. However, the sec8-9 mutation and to a lesser extent the secl0-2 mutation result in a shift of Sec15p to the plasma membrane, suggesting a role for these gene products in the regulation of the Sec15p membrane attachment/detachment processes. Depletion of Sec15p by repression of synthesis indicates that the plasma membrane bound pool is the most stable. During the course of these studies we have found that two activities associated with the yeast Golgi apparatus, Kex2 endopeptidase and GDPase, are in separable subcompartments.

Publication Date

1-1-1991

Publication Title

Journal of Cell Biology

ISSN

00219525

Volume

112

Issue

6

First Page

1117

Last Page

1131

PubMed ID

1900300

Digital Object Identifier (DOI)

10.1083/jcb.112.6.1117

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