The yeast Ca(2+)-ATPase homologue, PMR1, is required for normal Golgi function and localizes in a novel Golgi-like distribution

Mol Biol Cell. 1992 Jun;3(6):633-54. doi: 10.1091/mbc.3.6.633.

Abstract

PMR1, a Ca(2+)-adenosine triphosphatase (ATPase) homologue in the yeast Saccharomyces cerevisiae localizes to a novel Golgi-like organelle. Consistent with a Golgi localization, the bulk of PMR1 comigrates with Golgi markers in subcellular fractionation experiments, and staining of PMR1 by indirect immunofluorescence reveals a punctate pattern resembling Golgi staining in yeast. However, PMR1 shows only partial colocalization with known Golgi markers, KEX2 and SEC7, in double-label immunofluorescence experiments. The effect of PMR1 on Golgi function is indicated by pleiotropic defects in various Golgi processes in pmr1 mutants, including impaired proteolytic processing of pro-alpha factor and incomplete outer chain glycosylation of invertase. Consistent with the proposed role of PMR1 as a Ca2+ pump, these defects are reversed by the addition of millimolar levels of extracellular Ca2+, suggesting that Ca2+ disposition is essential to normal Golgi function. Absence of PMR1 function partially suppresses the temperature-sensitive growth defects of several sec mutants, and overexpression of PMR1 restricts the growth of others. Some of these interactions are modulated by changes in external Ca2+ concentrations. These results imply a global role for Ca2+ in the proper function of components governing transit and processing through the secretory pathway.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Transport / physiology
  • Calcium-Transporting ATPases / analysis
  • Calcium-Transporting ATPases / physiology*
  • Carboxypeptidases / analysis
  • Cathepsin A
  • Epitopes
  • Fungal Proteins / analysis
  • Fungal Proteins / metabolism*
  • Genes, Fungal / physiology
  • Glycosylation
  • Golgi Apparatus / chemistry*
  • Golgi Apparatus / metabolism
  • Hot Temperature
  • Mannose / metabolism
  • Mating Factor
  • Molecular Sequence Data
  • Mutation / physiology
  • Peptides / metabolism
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins

Substances

  • Epitopes
  • Fungal Proteins
  • Peptides
  • Saccharomyces cerevisiae Proteins
  • Mating Factor
  • Carboxypeptidases
  • Cathepsin A
  • PRC1 protein, S cerevisiae
  • serine carboxypeptidase
  • Calcium-Transporting ATPases
  • Mannose