First published online July 2, 2008
Journal of Cell Science 121, 1402e (2008)
© The Company of Biologists Limited
AFAP-110 – long live podosomes!
Podosomes – adhesive structures that form on the ventral surface of motile cells and actively degrade the extracellular matrix – are rich in filamentous actin. The actin-crosslinking protein AFAP-110, which promotes podosome formation, is known to be phosphorylated by PKC
, but the importance of AFAP-110 phosphorylation for podosome formation and stability is unclear. Using vascular smooth muscle (A7r5) cells, which form podosomes when treated with phorbol ester (PE), Daniel Flynn and colleagues (p. 2394) now show that AFAP-110 is phosphorylated at serine 277 (S277) in response to PE. Having generated a phosphospecific antibody against this site, the authors next show that the PH1 domain of AFAP-110 – which mediates its interactions with several PKC isoforms – is required for its phosphorylation; moreover, PKC
phosphorylates AFAP-110 at S277 in PE-stimulated COS-7 cells. In A7r5 cells, a phosphorylation-defective mutant of AFAP-110 (AFAP-110S277A) and S277-phosphorylated AFAP-110 both localise to podosomes. Intriguingly, however, podosomes in AFAP-110S277A-expressing cells are longer-lived than those in cells that express the wild-type protein. Thus, the PKC
-dependent phosphorylation of AFAP-110 appears to regulate podosome lifespan.
Related articles in JCS:
- Phosphorylation of AFAP-110 affects podosome lifespan in A7r5 cells
- Andrea Dorfleutner, YoungJin Cho, Deanne Vincent, Jess Cunnick, Hong Lin, Scott A. Weed, Christian Stehlik, and Daniel C. Flynn
JCS 2008 121: 2394-2405.
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