PMID:12134071

Citation	Qian, Y, Baisden, JM, Cherezova, L, Summy, JM, Guappone-Koay, A, Shi, X, Mast, T, Pustula, J, Zot, HG, Mazloum, N, Lee, MY and Flynn, DC (2002) PC phosphorylation increases the ability of AFAP-110 to cross-link actin filaments. Mol. Biol. Cell 13:2311-22
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 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.
Links	PubMed PMC117315 Online version:10.1091/mbc.E01-12-0148
Keywords	Actinin/metabolism; Actins/metabolism; Animals; Binding Sites; Cell Line; Cross-Linking Reagents/metabolism; Enzyme Activation; Leucine Zippers; Microfilament Proteins/genetics; Microfilament Proteins/metabolism; Phosphoproteins/genetics; Phosphoproteins/metabolism; Phosphorylation; Polymers/metabolism; Protein Binding; Protein Conformation; Protein Kinase C/metabolism; Recombinant Fusion Proteins/genetics; Recombinant Fusion Proteins/metabolism; Recombinant Proteins/genetics; Recombinant Proteins/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CHICK:AFAP1		GO:0003779: actin binding	ECO:0000314:		F		Figure 7 shows that PKC phosphorylation or leucine zipper deletion increases AFAp-110 ability to cross link actin filaments by incubating them with actin filaments (A) and incubating them with rhodamine-phalloidin-labeled actin filaments.	complete CACAO 9397

References

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