The spindle pole body protein Cdc11p links Sid4p to the fission yeast septation initiation network.
The Schizosaccharomyces pombe septation initiation network (SIN) signals the onset of cell division from the spindle pole body (SPB) and is regulated by the small GTPase Spg1p. The localization of SIN components including Spg1p to the SPB is required for cytokinesis and is dependent on Sid4p, a constitutive resident of SPBs. However, a direct interaction between Sid4p and other members of the SIN has not been detected. To understand how Sid4p is linked to other SIN components, we have begun to characterize an S. pombe homolog of the Saccharomyces cerevisiae SPB protein Nud1p. We have determined that this S. pombe Nud1p homolog corresponds to Cdc11p, a previously uncharacterized SIN element. We report that Cdc11p is present constitutively at SPBs and that its function appears to be required for the localization of all other SIN components to SPBs with the exception of Sid4p. The Cdc11p C terminus localizes the protein to SPBs in a Sid4p-dependent manner, and we demonstrate a direct Cdc11p-Sid4p interaction. The N-terminus of Cdc11p is required for Spg1p binding to SPBs. Our studies indicate that Cdc11p provides a physical link between Sid4p and the Spg1p signaling pathway.
Tomlin
Gregory C
GC
HHMI and Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Morrell
Jennifer L
JL
Gould
Kathleen L
KL
D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D003851:Deoxyribonucleases / Q000378:metabolism; D000939:Epitopes; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D049452:Green Fluorescent Proteins; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000378:metabolism; D008780:Methyltransferases; D008869:Microtubule-Associated Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013696:Temperature; D012359:tRNA Methyltransferases
C099502:CDC11 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D000939:Epitopes; D005656:Fungal Proteins; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C409024:Sid4 protein, S pombe; D049452:Green Fluorescent Proteins; D008780:Methyltransferases; C403804:SPB1 protein, S cerevisiae; D012359:tRNA Methyltransferases; D003851:Deoxyribonucleases; C077501:TRM2 protein, S cerevisiae