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

David A. Canton, Mary Ellen K. Olsten, Hanspeter Niederstrasser, John A. Cooper, David W. Litchfield

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


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.

Original languageEnglish
Pages (from-to)36347-36359
Number of pages13
JournalJournal of Biological Chemistry
Issue number47
StatePublished - Nov 24 2006


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