Nazarko V. The functional role of the proteins, involved in pexophagy in yeasts.

Research object: molecular mechanism of degradation of peroxisomas in baker's yeast Saccharomyces cerevisiae and methylotrophic yeast Pichia pastoris. Aim of work: to identify the new genes involved in pexophagy in P. pastoris, and investigate a role for pexophagy of some protein components of recognition of glucose in yeasts S. cerevisiae and P. pastoris. Research methods: methods of cell biology, molecular-genetic, biochemical, statistical. It is shown that components of сAMP-PKA signaling pathway, G-protein coupled receptor Gpr1 and G- protein Gpa2, involved in sensing of glucose in the process of pexophagy in baker's yeast S. cerevisiae, but not in methylotrophic yeast P. pastoris. It is shown that deletion of the gene of high-affinity glucose sensor SNF3 or gene of low-affinity glucose sensor RGT2, unlike the deletion of gene of GPCR sensor GPR1, insignificantly influences on degradation of peroxisomes in S. cerevisiae. However, deletion of genes of both sensors SNF3 and RGT2 substantially slows pexophagy. The search of proteins that in the yeast two-hybrid system interact with the protein Atg28 of P. pastoris is conducted, and the new autophagic protein named Atg35 is identified. It is shown that protein Atg35 of P. pastoris, as well as Atg28, participates in micropexophagy, namely, formation of MIPA, but, unlike Atg28, does not participate in macropexophagy, Сvt-pathway and non-specific macroautophagy. Sphere of the use: cytology, cellular biology.