Plk1 phosphorylates CLIP-170 and regulates its binding to microtubules for chromosome alignment.
The microtubule (MT) cytoskeleton is essential for cellular morphogenesis, cell migration, and cell division. MT organization is primarily mediated by a variety of MT-associated proteins. Among these proteins, plus-end-tracking proteins (+TIPs) are evolutionarily conserved factors that selectively accumulate at growing MT plus ends. Cytoplasmic linker protein (CLIP)-170 is a +TIP that associates with diverse proteins to determine the behavior of MT ends and their linkage to intracellular structures, including mitotic chromosomes. However, how CLIP-170 activity is spatially and temporally controlled is largely unknown. Here, we show that phosphorylation at Ser312 in the third serine-rich region of CLIP-170 is increased during mitosis. Polo-like kinase 1 (Plk1) is responsible for this phosphorylation during the mitotic phase of dividing cells. In vitro analysis using a purified CLIP-170 N-terminal fragment showed that phosphorylation by Plk1 diminishes CLIP-170 binding to the MT ends and lattice without affecting binding to EB3. Furthermore, we demonstrate that during mitosis, stable kinetochore/MT attachment and subsequent chromosome alignment require CLIP-170 and a proper phosphorylation/dephosphorylation cycle at Ser312. We propose that CLIP-170 phosphorylation by Plk1 regulates proper chromosome alignment by modulating the interaction between CLIP-170 and MTs in mitotic cells and that CLIP-170 activity is stringently controlled by its phosphorylation state, which depends on the cellular context.
Department of Cell Pharmacology, Nagoya University Graduate School of Medicine.
Mai
M
Kakeno
Kenji
K
Matsuzawa
Toshinori
T
Matsui
Hiroki
H
Akita
Ikuko
I
Sugiyama
Fumiyoshi
F
Ishidate
Atsushi
A
Nakano
Seiji
S
Takashima
Hidemasa
H
Goto
Masaki
M
Inagaki
Kozo
K
Kaibuchi
Takashi
T
Watanabe
D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002877:Chromosomes, Human / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis; D009363:Neoplasm Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D058105:Polymerization; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D000097869:Polo-Like Kinase 1
D018797:Cell Cycle Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012694:Serine; D000097869:Polo-Like Kinase 1; C076744:cytoplasmic linker protein 170