Open AccessDependence of S accharomyces cerevisiae G olgi functions on V ‐ ATP ase activity
Author(s) -
Corbacho Isaac,
Teixidó Francisco,
Olivero Isabel,
Hernández Luis M.
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2011.00784.x
Subject(s) - golgi apparatus , biology , vacuole , saccharomyces cerevisiae , microbiology and biotechnology , mutant , secretory pathway , v atpase , atpase , biochemistry , endoplasmic reticulum , enzyme , yeast , cytoplasm , gene
The V ‐ ATP ase of S accharomyces cerevisiae is an ATP ‐dependent proton pump responsible for acidification of the vacuole and other internal compartments including the whole secretory pathway. We have studied the behavior of several glycoprotein processing reactions occurring in different G olgi compartments of representative vmaΔ mutants. We found that outer chain initiation is not altered in the mutants while mannosylphosphate transfer, α(1,3)‐linked mannoses addition, and α factor maturation seem to be affected. The results suggest a gradation in the dependence of G olgi functions on V ‐ ATP ase activity, from early G olgi (unaffected) to late G olgi (significantly reduced). These findings are in agreement with the internal pH of G olgi cisternae measured in mammalian cells, which is more acidic in the late region. The mutant defects can be partially restored by buffering the external medium to pH 6.0, which supports the existence of a mechanism that, in the absence of a functional V ‐ ATP ase, could contribute to pH regulation at least in the late G olgi.