The meiosis-specific Sid2p-related protein Slk1p regulates forespore membrane assembly in fission yeast.
Cytokinesis in all organisms involves the creation of membranous barriers that demarcate individual daughter cells. In fission yeast, a signaling module termed the septation initiation network (SIN) plays an essential role in the assembly of new membranes and cell wall during cytokinesis. In this study, we have characterized Slk1p, a protein-kinase related to the SIN component Sid2p. Slk1p is expressed specifically during meiosis and localizes to the spindle pole bodies (SPBs) during meiosis I and II in a SIN-dependent manner. Slk1p also localizes to the forespore membrane during sporulation. Cells lacking Slk1p display defects associated with sporulation, leading frequently to the formation of asci with smaller and/or fewer spores. The ability of slk1 Delta cells to sporulate, albeit inefficiently, is fully abolished upon compromise of function of Sid2p, suggesting that Slk1p and Sid2p play overlapping roles in sporulation. Interestingly, increased expression of the syntaxin Psy1p rescues the sporulation defect of sid2-250 slk1 Delta. Thus, it is likely that Slk1p and Sid2p play a role in forespore membrane assembly by facilitating recruitment of components of the secretory apparatus, such as Psy1p, to allow membrane expansion. These studies thereby provide a novel link between the SIN and vesicle trafficking during cytokinesis.
Yan
Hongyan
H
Cell Division Laboratory, Department of Biological Sciences, National University of Singapore, Singapore.
Ge
Wanzhong
W
Chew
Ting Gang
TG
Chow
Jeng Yeong
JY
McCollum
Dannel
D
Neiman
Aaron M
AM
Balasubramanian
Mohan K
MK
D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D048749:Cytokinesis; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008540:Meiosis; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D011494:Protein Kinases / Q000378:metabolism*; D050765:Qa-SNARE Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000235:genetics* / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
C510389:Psy1 protein, S pombe; D050765:Qa-SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; C113816:Sid2 protein, S pombe; C072075:BCK1 protein, S cerevisiae; D020929:Mitogen-Activated Protein Kinase Kinases