Dom34 Links Translation to Protein O-mannosylation

Area of Science:

• Molecular Biology
• Mycology
• Biochemistry

Background:

• Dom34 protein is known to regulate translation by managing ribosomal subunit levels.
• Protein O-mannosyltransferase (Pmt) enzymes are crucial for proper protein glycosylation in eukaryotes.
• Fungal pathogens like Candida albicans rely on efficient glycosylation for virulence and survival.

Purpose of the Study:

• To investigate the interaction between Dom34 and Pmt1 in Saccharomyces cerevisiae and Candida albicans.
• To elucidate the role of Dom34 in regulating the translation of PMT gene transcripts, especially under glycostress conditions.
• To characterize the RNA-binding activity of Dom34 at the 5'-UTR of PMT transcripts.

Main Methods:

• Genetic interaction studies in yeast and C. albicans.
• Analysis of protein and transcript levels using Western blotting and RT-qPCR.
• In vitro translation assays using recombinant Dom34 and PMT1 5'-UTR RNA.
• Polysomal profiling to assess translational efficiency.

Main Results:

• Dom34 genetically interacts with Pmt1; loss of Dom34 exacerbates pmt1 mutant defects, while its overexpression ameliorates them.
• Dom34 overproduction increases Pmt1 protein levels without affecting PMT1 transcript levels.
• Dom34 directly binds to a CA/AC-rich sequence in the 5'-UTR of the PMT1 transcript, regulating in vitro translation.
• Dom34 specifically enhances the translation of transcripts encoding Pmt isoforms 1, 4, and 6, with moderate effects on general translation.

Conclusions:

• Dom34 plays a specific role in translational upregulation of PMT transcripts, optimizing cellular responses to glycostress.
• This translational function, mediated by RNA binding at the 5'-UTR, adds a new dimension to Dom34's known functions.
• Dom34 is a key regulator linking translational control to cellular responses to protein glycosylation defects.