Objective: The purpose of this article is to study the underlying cause of the induction of autophagy in Pichia pastoris cells grown in amino acid-rich methanol medium during methanol adaptation.
Results: Autophagy was induced in P. pastoris GS115 when cells were grown in amino acid-rich methanol medium. Transcriptome analysis revealed that genes involved in amino acid biosynthesis were upregulated. The deletion of Gcw13, a GPI-anchored protein that plays a role in the endocytosis of the general amino acid permease Gap1, resulted in the inhibition of autophagy, the activation of TORC1 and an increase in the uptake of glutamine and asparagine in methanol-grown cells.
Conclusions: Our results demonstrated that the autophagy induced in P. pastoris cells grown in amino acid-rich methanol medium was nitrogen source independent and may be due to a Gcw13-dependent decrease in amino acid uptake during methanol adaptation.
Keywords: Amino acid starvation; Autophagy; Gcw13; Pichia pstoris; TORC1.