Slk1 is a meiosis-specific Sid2-related kinase that coordinates meiotic nuclear division with growth of the forespore membrane

Abstract

Resultsslk1 is a meiosis-specific sid2 paralogue The slk1 (mug27) gene was identified in a large-scale-deletion screening of meiotically upregulated genes (Martin-Castellanos et al., 2005). Viable mug mutants (167 in total) were systematically Septation and spore formation in fission yeast are compartmentalization processes that occur during the mitotic and meiotic cycles, and that are regulated by the septation initiation network (SIN). In mitosis, activation of Sid2 protein kinase transduces the signal from the spindle pole body (SPB) to the middle of the cell in order to promote the constriction of the actomyosin ring. Concomitant with ring contraction, membrane vesicles are added at the cleavage site to enable the necessary expansion of the cell membrane. In meiosis, the forespore membrane is synthesized from the outer layers of the SPB by vesicle fusion. This membrane grows and eventually engulfs each of the four haploid nuclei. The molecular mechanism that connects the SIN pathway with synthesis of the forespore membrane is poorly understood. Here, we describe a meiosis-specific Sid2-like kinase (Slk1), which is important for the coordination of the growth of the forespore membrane with the meiotic nuclear divisions. Slk1 and Sid2 are required for forespore membrane biosynthesis and seem to be the final output of the SIN pathway in meiosis.Supplementary material available online at http://jcs.biologists.org/cgi/content/full/121/9/1383/DC1 Key words: Meiosis, Forespore membrane, Sporulation, SIN, Sid2, Slk1 SummarySlk1 is a meiosis-specific Sid2-related kinase that coordinates meiotic nuclear division with growth of the forespore membrane

The role ofSchizosaccharomyces pombe dma1in spore formation during meiosis

“…Because mug27-D cells produce small spores, whereas 3289 dma1 in spore formation dma1-D cells produce large spores, we tested whether the steadystate levels of mug27p were affected in dma1-D. We observed that mug27p levels peaked at the transition from meiosis I to meiosis II and then declined at the time of spore formation (Fig. 8A), consistent with previous studies (Ohtaka et al, 2008;Perez-Hidalgo et al, 2008;Yan et al, 2008). By contrast, in dma1-D meiosis, mug27p persisted beyond the onset of meiosis II (Fig.…”

“…A sid2p-related kinase called mug27 (also known as ppk35 or slk1; hereafter called mug27) is expressed during meiosis (Ohtaka et al, 2008;Perez-Hidalgo et al, 2008;Yan et al, 2008). A sid2-250 mug27-D double mutant makes no spores at all, indicating that the two kinases cooperate.…”

The Meiosis-Specific Sid2p-related Protein Slk1p Regulates Forespore Membrane Assembly in Fission Yeast

“…Slk1p has been identified as the product of the mug27 gene (meiotic up-regulated gene-27) from a microarray based analysis of genes expressed during meiosis, and its expression has not been detected in mitotically growing vegetative cells (Martin-Castellanos et al, 2005). Slk1p has been independently characterized by two other research groups recently and these authors arrive largely at similar conclusions (Ohtaka et al, 2008;Perez-Hidalgo et al, 2008).…”

“…Slk1p has been identified as the product of the mug27 gene (meiotic up-regulated gene-27) from a microarray based analysis of genes expressed during meiosis, and its expression has not been detected in mitotically growing vegetative cells (Martin-Castellanos et al, 2005). Slk1p has been independently characterized by two other research groups recently and these authors arrive largely at similar conclusions (Ohtaka et al, 2008;Perez-Hidalgo et al, 2008).Although the regions of high similarity between Slk1p and Sid2p lie in the protein kinase domain (ϳ51% identity), the nonkinase domains are also related, in that the amino acids upstream of the kinase domain exhibit 18% identity, whereas those downstream of the kinase domain exhibit 28% identity. Slk1p, like Sid2p, contains activatory phosphorylation sites within the kinase domain (serine 356) and the nonkinase domain (threonine 537).…”

Spo5 phosphorylation is essential for its own timely degradation and for successful meiosis inSchizosaccharomyces pombe

“…Time course observations revealed that this "lysed phenotype" was already apparent 14 h after meiotic induction, and a subsequent delay in meiotic progression when the meiotic recombination checkpoint is activated. 6 The meiosis-specific Slk1 (Mug27) kinase, a paralog of septation initiation kinase Sid2, regulates FSM assembly and sporulation. [7][8][9] We previously reported that Spo5 protein levels during meiosis are somehow regulated by Spo5 phosphorylation-dependent proteolysis.…”