Ca2+-ATPases of Saccharomyces cerevisiae: diversity and possible role in protein sorting

Okorokov, Lev A. and Lehle, Ludwig (1998) Ca2+-ATPases of Saccharomyces cerevisiae: diversity and possible role in protein sorting. FEMS MICROBIOLOGY LETTERS, 162 (1). pp. 83-91. ISSN 0378-1097, 1574-6968

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Abstract

The PMR1 gene of Saccharomyces cerevisiae is thought to encode a putative Ca2+-ATPase [1]. Membranes isolated from wild-type cells and from pmr1 null mutant of S. cerevisiae were fractionated on sucrose density gradients. In the pmr1 mutant we found a decrease in activity of the P-type ATPase and of ATP-dependent, protonophore-insensitive Ca2+ transport in light membranes, that comigrate with the Golgi marker GDPase. We conclude that the product of the PMR1 gene (Pmr1p) is indeed a Ca2+-ATPase of the Golgi and Golgi-like membranes. Surprisingly, the pmr1 null mutation abolished Ca2+-ATPase activity in Golgi and/or Golgi-like membranes only to 50% under conditions where they are separated from vacuolar membranes. This indicates that an additional Ca2+-ATPase is localized in Golgi and/or Golgi-like membranes. Moreover, a third Ca2+-ATPase is found in the ER and ER-like membranes. The data are consistent with the assumption that these Ca2+-ATPases are encoded by gene(s) different from PMR1. Disruption of PMR1 Ca2+-ATPase causes significant redistribution of enzyme activities and of total protein in compartments of the secretory pathway. A decrease in activity is observed for three integral membrane proteins: NADPH cytochrome c reductase, dolichyl phosphate mannose synthase, and Ca2+-ATPase, and also for total protein in Golgi, Golgi-like compartments and in vacuoles, whereas a corresponding increase of these activities is observed in endoplasmic reticulum and endoplasmic reticulum-like membranes. We assume that Ca2+-ATPases and sufficient Ca2+ gradients across the organellar membranes are important for the correct sorting of proteins to the various compartments of the secretory apparatus. (C) 1998 Published by Elsevier Science B.V.

Item Type: Article
Uncontrolled Keywords: ENDOPLASMIC-RETICULUM; SECRETORY PROTEINS; VACUOLAR MEMBRANE; YEAST; ATPASE; COMPARTMENTS; TRANSPORT; CARLSBERGENSIS; IDENTIFICATION; GLYCOSYLATION; Ca2+-adenosine triphosphatase; Ca2+ storage compartment; protein sorting; secretory pathway; Saccharomyces cerevisiae
Subjects: 500 Science > 570 Life sciences
500 Science > 580 Botanical sciences
Divisions: Biology, Preclinical Medicine > Institut für Pflanzenwissenschaften > Lehrstuhl für Zellbiologie und Pflanzenphysiologie (Prof. Dr. Klaus Grasser)
Depositing User: Dr. Gernot Deinzer
Date Deposited: 24 Feb 2023 08:54
Last Modified: 24 Feb 2023 08:54
URI: https://pred.uni-regensburg.de/id/eprint/49836

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