Roles of the DYRK Kinase Pom2 in Cytokinesis, Mitochondrial Morphology, and Sporulation in Fission Yeast

Abstract

Pom2 is predicted to be a dual-specificity tyrosine-phosphorylation regulated kinase (DYRK) related to Pom1 in Schizosaccharomyces pombe. DYRKs share a kinase domain capable of catalyzing autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. Here we show that Pom2 is functionally different from the well-characterized Pom1, although they share 55% identity in the kinase domain and the Pom2 kinase domain functionally complements that of Pom1. Pom2 localizes to mitochondria throughout the cell cycle and to the contractile ring during late stages of cytokinesis. Overexpression but not deletion of pom2 results in severe defects in cytokinesis, indicating that Pom2 might share an overlapping function with other proteins in regulating cytokinesis. Gain and loss of function analyses reveal that Pom2 is required for maintaining mitochondrial morphology independently of microtubules. Intriguingly, most meiotic pom2Δ cells form aberrant asci with meiotic and/or forespore membrane formation defects. Taken together, Pom2 is a novel DYRK kinase involved in regulating cytokinesis, mitochondrial morphology, meiosis, and sporulation in fission yeast.

The Rho-GEF Gef3 interacts with the septin complex and activates the GTPase Rho4 during fission yeast cytokinesis

“…Because Rho3 modulates exocytosis and regulates cell separation ( Wang et al. , 2003 ; Kita et al. , 2011 ), we tested its localization in gef3∆ , although our in vitro binding and genetic data do not support that Rho3 is Gef3 substrate.…”

“…, 2002 ; Wang et al. , 2003 ; Kita et al. , 2011 ), we also tested the genetic interactions between rho3∆ and scw1∆ or gef1∆ ( Figure 6, A–D , and Table 1 ).…”

Roles of the TRAPP-II Complex and the Exocyst in Membrane Deposition during Fission Yeast Cytokinesis

“…BFA (Sigma, B7651) treatment was performed at a final concentration of 50 μg/ml from a 5 mg/ml stock solution in ethanol for 10 min with rotation [ 125 ]. To test whether cortical localization of Syb1 at the division site depends on microtubules, cells were treated with MBC at a final concentration of 25 μg/ml for 10 min and then imaged on gelatin slide with the same drug concentration [ 126 ].…”

Roles of the fission yeast UNC-13/Munc13 protein Ync13 in late stages of cytokinesis

“…One microliter of 1 mg/ml Calcofluor stock solution was added, and the samples were incubated in the dark for 1 min before imaging. For methyl benzimidazole-2-yl carbamate (MBC) treatment, 1 ml cells were incubated with 5 µl 5 mg/ml MBC or DMSO for 15 min before mounting on the gelatin pad with the same concentration of MBC or DMSO for imaging ( Wu et al. , 2011 ; Wang et al.…”