Characterization of NIP2/centrobin, a novel substrate of Nek2, and its potential role in microtubule stabilization.
Nek2 is a mitotic kinase whose activity varies during the cell cycle. It is well known that Nek2 is involved in centrosome splitting, and a number of studies have indicated that Nek2 is crucial for maintaining the integrity of centrosomal structure and microtubule nucleation activity. In the present study, we report that NIP2, previously identified as centrobin, is a novel substrate of Nek2. NIP2 was daughter-centriole-specific, but was also found in association with a stable microtubule network of cytoplasm. Ectopic NIP2 formed aggregates but was dissolved by Nek2 into small pieces and eventually associated with microtubules. Knockdown of NIP2 showed significant reduction of microtubule organizing activity, cell shrinkage, defects in spindle assembly and abnormal nuclear morphology. Based on our results, we propose that NIP2 has a role in stabilizing the microtubule structure. Phosphorylation may be crucial for mobilization of the protein to a new microtubule and stabilizing it.
Jeong
Yeontae
Y
Department of Biological Sciences and Research Center for Functional Cellulomics, Seoul National University, Seoul 151-742, Korea.
Lee
Jungmin
J
Kim
Kyeongmi
K
Yoo
Jae Cheal
JC
Rhee
Kunsoo
K
D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002502:Centrioles / Q000378:metabolism; D018385:Centrosome / Q000378:metabolism; D006801:Humans; D051379:Mice; D008870:Microtubules / Q000378:metabolism*; D000072379:NIMA-Related Kinases; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D008941:Spindle Apparatus / Q000378:metabolism; D020798:Two-Hybrid System Techniques
C507203:CNTROB protein, human; D018797:Cell Cycle Proteins; C089441:NEK2 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases