Sequestration of the exocytic SNARE Psy1 into multiprotein nodes reinforces polarized morphogenesis in fission yeast

Fission yeast cells prevent mitotic entry until a threshold cell surface area is reached. The protein kinase Cdr2 contributes to this size control system by forming multiprotein nodes that inhibit Wee1 at the medial cell cortex. Cdr2 node anchoring at the cell cortex is not fully understood. Through a genomic screen, we identified the conserved GTPase Arf6 as a component of Cdr2 signaling. Cells lacking Arf6 failed to divide at a threshold surface area and instead shifted to volume-based divisions at increased overall size. Arf6 stably localized to Cdr2 nodes in its GTP-bound but not GDP-bound state, and its guanine nucleotide exchange factor (GEF), Syt22, was required for both Arf6 node localization and proper size at division. In arf6Δ mutants, Cdr2 nodes detached from the membrane and exhibited increased dynamics. These defects were enhanced when arf6Δ was combined with other node mutants. Our work identifies a regulated anchor for Cdr2 nodes that is required for cells to sense surface area.

show abstract

Section: Methodsmentioning

confidence: 99%

Arf6 anchors Cdr2 nodes at the cell cortex to control cell size at division

Opalko

Miller

Kim

et al. 2021

Journal of Cell Biology

Self Cite

View full text Add to dashboard Cite

show abstract

“…FRAP analysis was performed using the LSM880 laser scanning confocal microscope described above and following previously described methods (Miller et al, 2021). Cells were imaged at a single focal plane in 12 EMM4S (Fig 3C , S3B) or YE4S (Fig S3C) at room temperature on lectin coated μ-slide 18 well Ibidi chambers (Cat 81811).…”

Section: Frapmentioning

confidence: 99%

Arf6 anchors Cdr2 nodes at the cell cortex to control cell size at division

Kim

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Fission yeast cells prevent mitotic entry until a threshold cell surface area is reached. The protein kinase Cdr2 contributes to this size control system by forming multiprotein nodes that inhibit Wee1 at the medial cell cortex. Cdr2 node anchoring at the cell cortex is not fully understood. Through a genomic screen, we identified the conserved GTPase Arf6 as a component of Cdr2 signaling. Cells lacking Arf6 failed to divide at a threshold surface area and instead shifted to volume-based divisions at increased overall size. Arf6 stably localized to Cdr2 nodes in its GTP-bound but not GDP-bound state, and its GEF (guanine nucleotide exchange factor) Syt22 was required for both Arf6 node localization and proper size at division. In arf6∆ mutants, Cdr2 nodes detached from the membrane and exhibited increased dynamics. These defects were enhanced when arf6∆ was combined with other node mutants. Our work identifies a regulated anchor for Cdr2 nodes that is required for cells to sense surface area.

show abstract

“…Skb1 has been implicated in a wide range of pathways, including cell morphology and cell cycle regulation. Skb1 interacts with Slf1 and localizes to cell cortical nodes depending on Slf1, promoting rod-like cell morphology of fission yeast 40 , 41 . The DYRK-family kinase Pom1 negatively regulates cell cycle progression to ensure that cells grow to a certain size before entering mitosis 42 .…”

Section: Resultsmentioning

confidence: 99%

“…In contrast to srr1 , the skb1 deletion does not increase DNA damage sensitivity and, intriguingly, reduces chromosome loss in rad51Δ cells. Loss of Slf1 40 , 41 or Pom1 42 , 43 , which functions with Skb1 in cell morphology and cell cycle regulation, did not reduce GCRs. However, mutating conserved residues in the arginine methyltransferase (RMTase) domain of Skb1 strongly reduced GCRs, suggesting that Skb1 causes isochromosome formation through its RMTase activity.…”

Section: Introductionmentioning

confidence: 84%

Fission yeast Srr1 and Skb1 promote isochromosome formation at the centromere

et al. 2023

View full text Add to dashboard Cite

Rad51 maintains genome integrity, whereas Rad52 causes non-canonical homologous recombination leading to gross chromosomal rearrangements (GCRs). Here we find that fission yeast Srr1/Ber1 and Skb1/PRMT5 promote GCRs at centromeres. Genetic and physical analyses show that srr1 and skb1 mutations reduce isochromosome formation mediated by centromere inverted repeats. srr1 increases DNA damage sensitivity in rad51 cells but does not abolish checkpoint response, suggesting that Srr1 promotes Rad51-independent DNA repair. srr1 and rad52 additively, while skb1 and rad52 epistatically reduce GCRs. Unlike srr1 or rad52, skb1 does not increase damage sensitivity. Skb1 regulates cell morphology and cell cycle with Slf1 and Pom1, respectively, but neither Slf1 nor Pom1 causes GCRs. Mutating conserved residues in the arginine methyltransferase domain of Skb1 greatly reduces GCRs. These results suggest that, through arginine methylation, Skb1 forms aberrant DNA structures leading to Rad52-dependent GCRs. This study has uncovered roles for Srr1 and Skb1 in GCRs at centromeres.

show abstract

Sequestration of the exocytic SNARE Psy1 into multiprotein nodes reinforces polarized morphogenesis in fission yeast

Cited by 4 publications

References 58 publications

Arf6 anchors Cdr2 nodes at the cell cortex to control cell size at division

Arf6 anchors Cdr2 nodes at the cell cortex to control cell size at division

Arf6 anchors Cdr2 nodes at the cell cortex to control cell size at division

Fission yeast Srr1 and Skb1 promote isochromosome formation at the centromere

Contact Info

Product

Resources

About