PC phosphorylation increases the ability of AFAP-110 to cross-link actin filaments.
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 Src(527F) 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.
Mesh Terms:
Actinin, Actins, Animals, Binding Sites, Cell Line, Cross-Linking Reagents, Enzyme Activation, Leucine Zippers, Microfilament Proteins, Phosphoproteins, Phosphorylation, Polymers, Protein Binding, Protein Conformation, Protein Kinase C, Recombinant Fusion Proteins, Recombinant Proteins
Actinin, Actins, Animals, Binding Sites, Cell Line, Cross-Linking Reagents, Enzyme Activation, Leucine Zippers, Microfilament Proteins, Phosphoproteins, Phosphorylation, Polymers, Protein Binding, Protein Conformation, Protein Kinase C, Recombinant Fusion Proteins, Recombinant Proteins
Mol. Biol. Cell
Date: Jul. 01, 2002
PubMed ID: 12134071
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