The role of CKIP-1 in cell morphology depends on its interaction with actin-capping protein

J Biol Chem. 2006 Nov 24;281(47):36347-59. doi: 10.1074/jbc.M607595200. Epub 2006 Sep 20.


CKIP-1 is a pleckstrin homology domain-containing protein that induces alterations of the actin cytoskeleton and cell morphology when expressed in human osteosarcoma cells. CKIP-1 interacts with the heterodimeric actin-capping protein in cells, so we postulated that this interaction was responsible for the observed cytoskeletal and morphological effects of CKIP-1. To test this postulate, we used peptide "walking arrays" and alignments of CKIP-1 with CARMIL, another CP-binding protein, to identify Arg-155 and Arg-157 of CKIP-1 as residues potentially required for its interactions with CP. CKIP-1 mutants harboring Arg-155 and Arg-157 substitutions exhibited greatly decreased CP binding, while retaining wild-type localization, the ability to interact with protein kinase CK2, and self-association. To examine the phenotype associated with expression of these mutants, we generated tetracycline-inducible human osteosarcoma cells lines expressing R155E,R157E mutants of CKIP-1. Examination of these cell lines reveals that CKIP-1 R155E,R157E did not induce the distinct changes in cell morphology and the actin cytoskeleton that are characteristic of wild-type CKIP-1 demonstrating that the interaction between CKIP-1 and CP is required for these cellular effects.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / chemistry*
  • Amino Acid Sequence
  • Animals
  • Arginine / chemistry
  • Carrier Proteins / metabolism
  • Carrier Proteins / physiology*
  • Casein Kinase II / metabolism
  • Cell Line, Tumor
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Molecular Sequence Data
  • Mutation
  • Osteosarcoma / metabolism
  • Peptides / chemistry
  • Phalloidine / pharmacology
  • Protein Binding
  • Sequence Homology, Amino Acid


  • Actins
  • Carrier Proteins
  • Intracellular Signaling Peptides and Proteins
  • PLEKHO1 protein, human
  • Peptides
  • Phalloidine
  • Arginine
  • Casein Kinase II