Cdk1 Phosphorylates Drosophila Sas-4 to Recruit Polo to Daughter Centrioles and Convert Them to Centrosomes.
Centrosomes and cilia are organized by a centriole pair comprising an older mother and a younger daughter. Centriole numbers are tightly regulated, and daughter centrioles (which assemble in S phase) cannot themselves duplicate or organize centrosomes until they have passed through mitosis. It is unclear how this mitotic "centriole conversion" is regulated, but it requires Plk1/Polo kinase. Here we show that in flies, Cdk1 phosphorylates the conserved centriole protein Sas-4 during mitosis. This creates a Polo-docking site that helps recruit Polo to daughter centrioles and is required for the subsequent recruitment of Asterless (Asl), a protein essential for centriole duplication and mitotic centrosome assembly. Point mutations in Sas-4 that prevent Cdk1 phosphorylation or Polo docking do not block centriole disengagement during mitosis, but block efficient centriole conversion and lead to embryonic lethality. These observations can explain why daughter centrioles have to pass through mitosis before they can duplicate and organize a centrosome.
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Zsofia A
ZA
Novak
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Alan
A
Wainman
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Lisa
L
Gartenmann
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. Electronic address: jordan.raff@path.ox.ac.uk.
Jordan W
JW
Raff
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D002502:Centrioles / Q000378:metabolism*; D018385:Centrosome / Q000378:metabolism*; D029721:Drosophila Proteins / Q000737:chemistry / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D008869:Microtubule-Associated Proteins; D008938:Mitosis; D008954:Models, Biological; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism
D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; C522063:Sas-4 protein, Drosophila; D013912:Threonine; C072004:polo protein, Drosophila; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; C000601753:Cdk1 protein, Drosophila