Las21 participates in extracellular/cell surface phenomena in Saccharomyces cerevisiae.

Abstract

Las21 (Yjl062W) is a member of the major facilitator super family, possessing multimembrane spanning domains. The LAS21 gene was identified as a responsible gene for a Saccharomyces cerevisiae mutan which shows sensitivity to a local anestheticum, tetracaine. The null las21 mutant (las21∆) is viable but shows temperature sensitive growth. We found, in addition to this phenotype, that the las21∆ strain shows a number of defects; mating deficiency, calcofluor resistance, and formation of Zymolyase sensitive spores. Temperature sensitive growth of the las21∆ mutant was found to be suppressed by 0.1 M MgSO 4 . Two multicopy suppressors were obtained. They are ECM33 (YBR078W) and PIR2/HSP150 (YJR159W) both have some roles in an extracellular function. The common features of the suppressors, genetic and physiological, of the las21∆ mutation suggest that Las21 participates in a global activity of extracellular phenomena. The las 21 phenotypes are consistent with the idea that Las21/Gpi7 acts in metabolism of glycosylphosphatidylinositol.

GPI7 Involved in Glycosylphosphatidylinositol Biosynthesis Is Essential for Yeast Cell Separation

“…Polarization of sterol-rich domains to the shmoo tip was observed in mating pheromone-treated cells in S. cerevisiae (54). The mating efficiency decreased to 1 ⁄100 of the wild-type level when both mating partners were gpi7⌬ strains (8). Lipid raft formation also contributes to the hyphal growth that is required for virulence in C. albicans (55).…”

“…Although several multicopy suppressors were isolated from gpi7⌬ cells (7,8,25), no significant information was obtained to elucidate the biological function of GPI7. Our purpose in this study was to obtain new suppressors from gpi7 missense and gpi7⌬ mutant cells, which may help to elucidate the biological functions of Gpi7p.…”

“…Multicopy Suppressors of gpi7-2 Mutant-Previous studies of GPI7 showed that PKC1, ECM33, PIR2, and PSD1 acted as multicopy suppressors in strain gpi7⌬ (7,8,25). Although several multicopy suppressors were isolated using the gpi7⌬ mutant, new suppressors that suggest the biological function of GPI7 may still be obtained from the gpi7-2 missense mutant.…”

“…GPI7 is not essential for cell viability, and GPI lacking a side chain EtN-P due to the loss of GPI7 function is still transferred to proteins (4 -6). Deletion of GPI7 causes a growth defect at high temperature, hypersensitivity to calcofluor white, and a decreased replacement of primary lipid moiety of GPI anchors by ceramide (5,7,8). Mutations in GPI7 also affect cell wall anchorage in S. cerevisiae and Candida albicans (9).…”

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

“…Essential Gpi11 was implicated at this step because Gpi11-deficient cells have similar GPI precursor accumulation profiles to gpi7D . The Etn-P on Man-2 enhances transfer of GPIs to protein, ER-to-Golgi transport of GPI proteins, GPI lipid remodeling to ceramide, transfer of GPI proteins to the wall, and targeting of certain GPI-anchored proteins in daughter cells Toh-E and Oguchi 1999;Richard et al 2002;Fujita et al 2004). …”