Genetic Evidence for the Role of the Vacuole in Supplying Secretory Organelles with Ca2+ in Hansenula polymorpha

Abstract

Processes taking place in the secretory organelles require Ca2+ and Mn2+, which in yeast are supplied by the Pmr1 ion pump. Here we observed that in the yeast Hansenula polymorpha Ca2+ deficiency in the secretory pathway caused by Pmr1 inactivation is exacerbated by (i) the ret1-27 mutation affecting COPI-mediated vesicular transport, (ii) inactivation of the vacuolar Ca2+ ATPase Pmc1 and (iii) inactivation of Vps35, which is a component of the retromer complex responsible for protein transport between the vacuole and secretory organelles. The ret1-27 mutation also exerted phenotypes indicating alterations in transport between the vacuole and secretory organelles. These data indicate that ret1-27, pmc1 and vps35 affect a previously unknown Pmr1-independent route of the Ca2+ delivery to the secretory pathway. We also observed that the vacuolar protein carboxypeptidase Y receives additional modifications of its glycoside chains if it escapes the Vps10-dependent sorting to the vacuole.

Detection and Elimination of Cellular Bottlenecks in Protein-Producing Yeasts

“…In contrast, alternating results regarding protein secretion were obtained in H. polymorpha, P. pastoris and Y. lipolytica disrupted for PMR1, which might be partly attributed to a reduced viability of the strains thus eventually masking the positive effects on secretion [112][113][114][115]. Furthermore, it was recently demonstrated that there are also Pmr1-independent routes of Ca 2+ delivery to the secretory organelles operating in H. polymorpha [116].…”

The role of Ca2+ signaling in Parkinson's disease

“…Two of these function in endosomal compartments: the vacuolar protein sorting 35 (VPS35), which is important for vesicular transport from the endosomes to the Golgi, and the vacuolar protein sorting 13 (VPS13C), which is important for vesicular transport from the Golgi to the endosomes. These proteins affect Ca 2+ influx in the secretory pathway and protein recycling ( Table 1 ) ( Fokina et al, 2015 ; Mehta et al, 2016 ; Wang et al, 2016 ). The third is a lysosomal protein, LRRK2, that is linked through an unknown mechanism to the regulation of Ca 2+ homeostasis in this organelle ( Table 1 ) ( Funayama et al, 2002 ; Gómez-Suaga et al, 2012 ; Gómez-Suaga and Hilfiker, 2012 ; Hockey et al, 2015 ).…”

Michael Ter-Avanesyan (1949-2018) - life in science

“…This has led to emergence of an additional model organism in Michael's lab, namely methylotrophic yeast Hansenula polymorpha. Using Hansenula, it was shown that a defect of the retrograde vesicular transport between the secretory organelles affects calcium homeostasis, probably due to the disruption of calcium delivery from the vacuole to the endoplasmic reticulum [31,32]. Michael's team has also shown that, unlike S. cerevisiae, H. polymorpha lacking both Golgi apparatus Ca 2+ /Mn 2+ ATPase Pmr1 and vacuolar Ca 2+ ATPase Pmc1, dies not due to excess of Ca 2+ in the cytosol but due to Ca 2+ shortage in the secretory pathway [32].…”

“…Using Hansenula, it was shown that a defect of the retrograde vesicular transport between the secretory organelles affects calcium homeostasis, probably due to the disruption of calcium delivery from the vacuole to the endoplasmic reticulum [31,32]. Michael's team has also shown that, unlike S. cerevisiae, H. polymorpha lacking both Golgi apparatus Ca 2+ /Mn 2+ ATPase Pmr1 and vacuolar Ca 2+ ATPase Pmc1, dies not due to excess of Ca 2+ in the cytosol but due to Ca 2+ shortage in the secretory pathway [32]. The most recent study by Michael's lab, involving H. polymorpha as a model organism revealed a link between protein glycosylation and phosphate transport [33].…”