Sid4p-Cdc11p assembles the septation initiation network and its regulators at the S. pombe SPB.
The Schizosaccharomyces pombe septation initiation network (SIN) triggers actomyosin ring constriction, septation, and cell division. It is organized at the spindle pole body (SPB) by the scaffold proteins Sid4p and Cdc11p. Here, we dissect the contributions of Sid4p and Cdc11p in anchoring SIN components and SIN regulators to the SPB. We find that Sid4p interacts with the SIN activator, Plo1p, in addition to Cdc11p and Dma1p. While the C terminus of Cdc11p is involved in binding Sid4p, its N-terminal half is involved in a wide variety of direct protein-protein interactions, including those with Spg1p, Sid2p, Cdc16p, and Cdk1p-Cdc13p. Given that the localizations of the remaining SIN components depend on Spg1p or Cdc16p, these data allow us to build a comprehensive model of SIN component organization at the SPB. FRAP experiments indicate that Sid4p and Cdc11p are stable SPB components, whereas signaling components of the SIN are dynamically associated with these structures. Our results suggest that the Sid4p-Cdc11p complex organizes a signaling hub on the SPB and that this hub coordinates cell and nuclear division.
Morrell
Jennifer L
JL
Howard Hughes Medical Institute and Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Tomlin
Gregory C
GC
Rajagopalan
Srividya
S
Venkatram
Srinivas
S
Feoktistova
Anna S
AS
Tasto
Joseph J
JJ
Mehta
Sapna
S
Jennings
Jennifer L
JL
Link
Andrew
A
Balasubramanian
Mohan K
MK
Gould
Kathleen L
KL
D018797:Cell Cycle Proteins / Q000378:metabolism* / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D036681:Fluorescence Recovery After Photobleaching; D015151:Immunoblotting; D008869:Microtubule-Associated Proteins / Q000378:metabolism* / Q000502:physiology; D008954:Models, Biological; D016297:Mutagenesis, Site-Directed; D010957:Plasmids / Q000235:genetics; D011233:Precipitin Tests; D011485:Protein Binding; D012568:Schizosaccharomyces; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism* / Q000502:physiology; D008941:Spindle Apparatus / Q000378:metabolism* / Q000502:physiology; D020798:Two-Hybrid System Techniques
C477369:CDC11 protein, S pombe; D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins; C409024:Sid4 protein, S pombe