Dual transcriptional and post-transcriptional regulation by the bHLH proteins Rtg1 and RtgX in Komagataella phaffii.

ABSTRACT: In Saccharomyces cerevisiae, the basic helix-loop-helix (bHLH) transcription factors Rtg1 and Rtg3 mediate retrograde signaling. In Candida albicans, the Rtg1-Rtg3 complex regulates galactose and sphingolipid metabolism and contributes to virulence. In the methylotrophic yeast Komagataella phaffii (formerly Pichia pastoris), Rtg1 (KpRtg1) controls glutamate and methanol metabolism by regulating the synthesis of GDH2 (glutamate dehydrogenase 2), PEPCK (phosphoenolpyruvate carboxykinase), and AOX1 (alcohol oxidase 1). The function of the putative Rtg3 ortholog, designated here as KpRtgX, has remained unknown. In this study, we identify KpRtgX as the missing regulatory partner of KpRtg1. Deletion of either KpRTG1 or KpRTGX produces identical phenotypes, suggesting functional overlap. KpRtgX l

SUBMITTER: Rajak N 

PROVIDER: S-EPMC12781876 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature