Interaction of CDK5RAP2 with EB1 to track growing microtubule tips and to regulate microtubule dynamics.
Mutations in cdk5rap2 are linked to autosomal recessive primary microcephaly, and attention has been paid to its function at centrosomes. In this report, we demonstrate that CDK5RAP2 localizes to microtubules and concentrates at the distal tips in addition to centrosomal localization. CDK5RAP2 interacts directly with EB1, a prototypic member of microtubule plus-end tracking proteins, and contains the basic and Ser-rich motif responsible for EB1 binding. The EB1-binding motif is conserved in the CDK5RAP2 sequences of chimpanzee, bovine, and dog but not in those of rat and mouse, suggesting a function gained during the evolution of mammals. The mutation of the Ile/Leu-Pro dipeptide within the motif abolishes EB1 interaction and plus-end attachment. In agreement with the mutational analysis, suppression of EB1 expression inhibits microtubule tip-tracking of CDK5RAP2. We have also found that the CDK5RAP2-EB1 complex regulates microtubule dynamics and stability. CDK5RAP2 depletion by RNA interference impacts the dynamic behaviors of microtubules. The CDK5RAP2-EB1 complex induces microtubule bundling and acetylation when expressed in cell cultures and stimulates microtubule assembly and bundle formation in vitro. Collectively, these results show that CDK5RAP2 targets growing microtubule tips in association with EB1 to regulate microtubule dynamics.
Fong
Ka-Wing
KW
Department of Biochemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Hau
Shiu-Yeung
SY
Kho
Yik-Shing
YS
Jia
Yue
Y
He
Lisheng
L
Qi
Robert Z
RZ
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D018797:Cell Cycle Proteins; D002460:Cell Line; D018385:Centrosome / Q000378:metabolism; D004285:Dogs; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D002679:Pan troglodytes; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
C405929:CDK5RAP2 protein, human; D018797:Cell Cycle Proteins; C405804:EB1 microtubule binding proteins; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins