Reactivating an Actin Regulator

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Science  21 Jan 2005:
Vol. 307, Issue 5708, pp. 321
DOI: 10.1126/science.307.5708.321c

Control of the actin cytoskeleton is critical for many cellular processes, particularly cell motility, and the actin-depolymerizing factor cofilin is inhibited by phosphorylation. Gohla et al. have identified a protein, named chronophin, with phosphatase activity toward phosphorylated cofilin. This enzyme is a member of the haloacid dehalogenase superfamily of phosphotransferases, which have a well-described catalytic mechanism as exemplified by the Ca2+-ATPase of sarco(endo)plasmic reticulum (see Olesen et al., Reports, 24 December 04, p. 2251) but have not previously been implicated in serine dephosphorylation in mammals. Overexpression of chronophin decreased the amount of phosphorylated cofilin in HeLa cells, whereas depletion by RNA interference increased the amounts of phosphorylated cofilin and F-actin, stabilized membrane protrusions and stress fibers, and induced abnormalities in cell division. These findings suggest that chronophin could be a therapeutic target in cases (for instance, chronophin is overexpressed in neuroblastomas) where control of the actin cytoskeleton is disrupted. — LBR

Nature Cell Biol. 7, 21 (2005).

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