Pichia pastoris 14-3-3 regulates transcriptional activity of the methanol inducible transcription factor Mxr1 by direct interaction

Pabitra K. Parua, Paul M. Ryan, Kayla Trang, Elton T. Young

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

The zinc-finger transcription factor, Mxr1 activates methanol utilization and peroxisome biogenesis genes in the methylotrophic yeast, Pichia pastoris. Expression of Mxr1-dependent genes is regulated in response to various carbon sources by an unknown mechanism. We show here that this mechanism involves the highly conserved 14-3-3 proteins. 14-3-3 proteins participate in many biological processes in different eukaryotes. We have characterized a putative 14-3-3 binding region at Mxr1 residues 212-225 and mapped the major activation domain of Mxr1 to residues 246-280, and showed that phenylalanine residues in this region are critical for its function. Furthermore, we report that a unique and previously uncharacterized 14-3-3 family protein in P. pastoris complements Saccharomyces cerevisiae 14-3-3 functions and interacts with Mxr1 through its 14-3-3 binding region via phosphorylation of Ser215 in a carbon source-dependent manner. Indeed, our in vivo results suggest a carbon source-dependent regulation of expression of Mxr1-activated genes by 14-3-3 in P. pastoris. Interestingly, we observed 14-3-3-independent binding of Mxr1 to the promoters, suggesting a post-DNA binding function of 14-3-3 in regulating transcription. We provide the first molecular explanation of carbon source-mediated regulation of Mxr1 activity, whose mechanism involves a post-DNA binding role of 14-3-3.

Original languageEnglish (US)
Pages (from-to)282-298
Number of pages17
JournalMolecular Microbiology
Volume85
Issue number2
DOIs
StatePublished - Jul 2012
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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