PC phosphorylation increases the ability of AFAP-110 to cross-link actin filaments

Yong Qian, Joseph M. Baisden, Lidia Cherezova, Justin M. Summy, Anne Guappone-Koay, Xianglin Shi, Tom Mast, Jennifer Pustula, Henry G. Zot, Nayef Mazloum, Marietta Y. Lee, Daniel C. Flynn

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

The actin filament-associated protein and Src-binding partner, AFAP-110, is an adaptor protein that links signaling molecules to actin filaments. AFAP-110 binds actin filaments directly and multimerizes through a leucine zipper motif. Cellular signals downstream of Src527F can regulate multimerization. Here, we determined recombinant AFAP-110 (rAFAP-110)-bound actin filaments cooperatively, through a lateral association. We demonstrate rAFAP-110 has the capability to cross-link actin filaments, and this ability is dependent on the integrity of the carboxy terminal actin binding domain. Deletion of the leucine zipper motif or PKC phosphorylation affected AFAP-110's conformation, which correlated with changes in multimerization and increased the capability of rAFAP-110 to cross-link actin filaments. AFAP-110 is both a substrate and binding partner of PKC. On PKC activation, stress filament organization is lost, motility structures form, and AFAP-110 colocalizes strongly with motility structures. Expression of a deletion mutant of AFAP-110 that is unable to bind PKC blocked the effect of PMA on actin filaments. We hypothesize that upon PKC activation, AFAP-110 can be cooperatively recruited to newly forming actin filaments, like those that exist in cell motility structures, and that PKC phosphorylation effects a conformational change that may enable AFAP-110 to promote actin filament cross-linking at the cell membrane.

Original languageEnglish
Pages (from-to)2311-2322
Number of pages12
JournalMolecular Biology of the Cell
Volume13
Issue number7
DOIs
StatePublished - 2002

ASJC Scopus subject areas

  • Medicine (all)

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