The human microcephaly protein STIL interacts with CPAP and is required for procentriole formation.
Centriole duplication involves the growth of a procentriole next to the parental centriole. Mutations in STIL and CPAP/CENPJ cause primary microcephaly (MCPH). Here, we show that human STIL has an asymmetric localization to the daughter centriole and is required for procentriole formation. STIL levels oscillate during the cell cycle. Interestingly, STIL interacts directly with CPAP and forms a complex with hSAS6. A natural mutation of CPAP (E1235V) that causes MCPH in humans leads to significantly lower binding to STIL. Overexpression of STIL induced the formation of multiple procentrioles around the parental centriole. STIL depletion inhibited normal centriole duplication, Plk4-induced centriole amplification, and CPAP-induced centriole elongation, and resulted in a failure to localize hSAS6 and CPAP to the base of the nascent procentriole. Furthermore, hSAS6 depletion hindered STIL targeting to the procentriole, implying that STIL and hSAS6 are mutually dependent for their centriolar localization. Together, our results indicate that the two MCPH-associated proteins STIL and CPAP interact with each other and are required for procentriole formation, implying a central role of centriole biogenesis in MCPH.
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Chieh-Ju C
CJ
Tang
Shin-Yi
SY
Lin
Wen-Bin
WB
Hsu
Yi-Nan
YN
Lin
Chien-Ting
CT
Wu
Yu-Chih
YC
Lin
Ching-Wen
CW
Chang
Kuo-Sheng
KS
Wu
Tang K
TK
Tang
D000818:Animals; D002417:Cattle; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D002502:Centrioles / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008831:Microcephaly / Q000235:genetics / Q000503:physiopathology*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding
C414735:CENPJ protein, human; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; C497202:SASS6 protein, human; C071236:STIL protein, human