Evidence for a role of CLIP-170 in the establishment of metaphase chromosome alignment

J Cell Biol. 1998 May 18;141(4):849-62. doi: 10.1083/jcb.141.4.849.

Abstract

CLIPs (cytoplasmic linker proteins) are a class of proteins believed to mediate the initial, static interaction of organelles with microtubules. CLIP-170, the CLIP best characterized to date, is required for in vitro binding of endocytic transport vesicles to microtubules. We report here that CLIP-170 transiently associates with prometaphase chromosome kinetochores and codistributes with dynein and dynactin at kinetochores, but not polar regions, during mitosis. Like dynein and dynactin, a fraction of the total CLIP-170 pool can be detected on kinetochores of unattached chromosomes but not on those that have become aligned at the metaphase plate. The COOH-terminal domain of CLIP-170, when transiently overexpressed, localizes to kinetochores and causes endogenous full-length CLIP-170 to be lost from the kinetochores, resulting in a delay in prometaphase. Overexpression of the dynactin subunit, dynamitin, strongly reduces the amount of CLIP-170 at kinetochores suggesting that CLIP-170 targeting may involve the dynein/dynactin complex. Thus, CLIP-170 may be a linker for cargo in mitosis as well as interphase. However, dynein and dynactin staining at kinetochores are unaffected by this treatment and further overexpression studies indicate that neither CLIP-170 nor dynein and dynactin are required for the formation of kinetochore fibers. Nevertheless, these results strongly suggest that CLIP-170 contributes in some way to kinetochore function in vivo.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • COS Cells
  • COUP Transcription Factors
  • Chromosomes / physiology*
  • Chromosomes, Human / physiology*
  • DNA-Binding Proteins / analysis
  • Dynactin Complex
  • Dyneins / analysis
  • Endocytosis
  • HeLa Cells
  • Humans
  • Metaphase
  • Microtubule-Associated Proteins / analysis
  • Microtubule-Associated Proteins / biosynthesis
  • Microtubule-Associated Proteins / physiology*
  • Mitosis
  • Neoplasm Proteins
  • Phenotype
  • Receptors, Steroid*
  • Recombinant Proteins / biosynthesis
  • Transcription Factors / analysis
  • Transfection
  • Tumor Cells, Cultured

Substances

  • COUP Transcription Factors
  • DCTN2 protein, human
  • DNA-Binding Proteins
  • Dynactin Complex
  • Microtubule-Associated Proteins
  • Neoplasm Proteins
  • Receptors, Steroid
  • Recombinant Proteins
  • Transcription Factors
  • cytoplasmic linker protein 170
  • Dyneins