Involvement of fission yeast Pdc2 in RNA degradation and P-body function

• DOI: 10.1261/rna.059766.116
• Publication Date: 2016-12-29T02:20:38Z
• Authors: Chun-Yu Wang; Yi-Ting Wang; Wan-Yi Hsiao; Shao-Win Wang
• Keywords: Cell Nucleus; 0301 basic medicine; Cytoplasm; Base Sequence; RNA Stability; Cell Cycle; Active Transport, Cell Nucleus; RNA-Binding Proteins; RNA, Fungal; Protein Serine-Threonine Kinases; Article; DNA-Binding Proteins; Fungal Proteins; 03 medical and health sciences; Glucose; RNA Cap-Binding Proteins; Gene Expression Regulation, Fungal; Exoribonucleases; Schizosaccharomyces; Humans; Schizosaccharomyces pombe Proteins; Pyruvate Decarboxylase; Transcription Factors

In this study we identified Pdc2, the fission yeast ortholog of human Pat1b protein, which forms a complex with Lsm1-7 and plays a role in coupling deadenylation and decapping. The involvement of Pdc2 in RNA degradation and P-body function was also determined. We found that Pdc2 interacts with Dcp2 and is required for decapping in vivo. Although not absolutely essential for P-body assembly, overexpression of Pdc2 enhanced P-body formation even in the absence of Pdc1, the fission yeast functional homolog of human Edc4 protein, indicating that Pdc2 also plays a role in P-body formation. Intriguingly, in the absence of Pdc2, Lsm1 was found to accumulate in the nucleus, suggesting that Pdc2 shuttling between nucleus and cytoplasm plays a role in decreasing the nuclear concentration of Lsm1 to increase Lsm1 in the cytoplasm. Furthermore, unlike other components of P-bodies, the deadenylase Ccr4 did not accumulate in P-bodies in cells growing under favorable conditions and was only recruited to P-bodies after deprivation of glucose in a Pdc2-Lsm1-dependent manner, indicating a function of Pdc2 in cellular response to environmental stress. In supporting this idea, pdc2 mutants are defective in recovery from glucose starvation with a much longer time to re-enter the cell cycle. In keeping with the notion that Pat1 is a nucleocytoplasmic protein, functioning also in the nucleus, we found that Pdc2 physically and genetically interacts with the nuclear 5′–3′ exonuclease Dhp1. A function of Pdc2-Lsm1, in concert with Dhp1, regulating RNA by promoting its decapping/destruction in the nucleus was suggested.