beta-Arrestins scaffold cofilin with chronophin to direct localized actin filament severing and membrane protrusions downstream of protease-activated receptor-2.
Protease-activated receptor-2 (PAR-2) mediates pro-inflammatory signals in a number of organs, including enhancing leukocyte recruitment to sites of injury and infection. At the cellular level, PAR-2 promotes activation of the actin filament-severing protein cofilin, which is crucial for the reorganization of the actin cytoskeleton and chemotaxis. These responses require the scaffolding functions of beta-arrestins; however, the mechanism by which beta-arrestins spatially regulate cofilin activity and the role of this pathway in primary cells has not been investigated. Here, using size-exclusion chromatography and co-immunoprecipitation, we demonstrate that PAR-2 promotes the formation of a complex containing beta-arrestins, cofilin, and chronophin (CIN) in primary leukocytes and cultured cells. Both association of cofilin with CIN and cell migration are inhibited in leukocytes from beta-arrestin-2(-/-) mice. We show that, in response to PAR-2 activation, beta-arrestins scaffold cofilin with its upstream activator CIN, to facilitate the localized generation of free actin barbed ends, leading to membrane protrusion. These studies suggest that a major role of beta-arrestins in chemotaxis is to spatially regulate cofilin activity to facilitate the formation of a leading edge, and that this pathway may be important for PAR-2-stimulated immune cell migration.
Zoudilova
Maria
M
Cell, Molecular, and Developmental Biology Program, University of California, Riverside, California 92521, USA.
Min
Jungah
J
Richards
Heddie L
HL
Carter
David
D
Huang
Timothy
T
DeFea
Kathryn A
KA
D008841:Actin Cytoskeleton / Q000378:metabolism*; D051339:Actin Depolymerizing Factors / Q000378:metabolism*; D000818:Animals; D019390:Arrestins / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D022081:Cell Surface Extensions / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D044464:Receptor, PAR-2 / Q000378:metabolism*; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins
D051339:Actin Depolymerizing Factors; C000605258:Arrb2 protein, mouse; D019390:Arrestins; D044464:Receptor, PAR-2; D000071560:beta-Arrestin 2; D000071557:beta-Arrestins; D010749:Phosphoprotein Phosphatases