Plk1 phosphorylates CLIP-170 and regulates its binding to microtubules for chromosome alignment

Cell Struct Funct. 2014;39(1):45-59. doi: 10.1247/csf.14001. Epub 2014 Jan 22.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Cycle Proteins / metabolism*
  • Chromosomes, Human / metabolism*
  • HeLa Cells
  • Humans
  • Kinetochores / metabolism
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / metabolism*
  • Mitosis
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / metabolism*
  • Phosphorylation
  • Polymerization
  • Protein Binding
  • Protein-Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins / metabolism*
  • Serine / metabolism

Substances

  • Cell Cycle Proteins
  • Microtubule-Associated Proteins
  • Neoplasm Proteins
  • Proto-Oncogene Proteins
  • cytoplasmic linker protein 170
  • Serine
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1