Cyclic strain promotes shuttling of PYK2/Hic-5 complex from focal contacts in osteoblast-like cells.
We showed that cyclic strain (CS) of osteoblastic cells induced tyrosine phosphorylation of two homologous tyrosine kinases FAK and PYK2, and of two homologous adaptor proteins paxillin and Hic5, with similar kinetics. Immunostaining showed that all four proteins were localized to focal contacts in controls. In contrast, the dynamics of their subcellular localization observed after CS differed. While FAK and paxillin remained at the focal contact, Hic-5 and PYK2 translocated outside ventral focal contacts as early as 30 min after CS and were sequestered by the cytoskeleton. Co-immunoprecipitation showed that the association of PYK2/Hic-5 and PYK2/FAK increased with time after strain while that of paxillin and Hic-5 decreased. Altogether these results suggested that CS regulates focal contact activity in osteoblasts by modulating PYK2-containing complexes in particular by shuttling out of the focal contact the adaptor Hic-5 and favoring the anchorage of FAK within contacts.
INSERM E366, St. Etienne, F-42023, France. Alain.Guignandon@univ-st-etienne.fr
Alain
A
Guignandon
Nadia
N
Boutahar
Aline
A
Rattner
Laurence
L
Vico
Marie-Hélène
MH
Lafage-Proust
D000818:Animals; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004548:Elasticity; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism*; D022001:Focal Adhesions / Q000502:physiology*; D060588:LIM Domain Proteins; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D051379:Mice; D008938:Mitosis / Q000502:physiology; D010006:Osteoblasts / Q000502:physiology*; D051419:Paxillin / Q000378:metabolism*; D010507:Periodicity; D010812:Physical Stimulation / Q000379:methods; D013314:Stress, Mechanical
D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D060588:LIM Domain Proteins; D051419:Paxillin; C496062:Pxn protein, mouse; C090090:Tgfb1i1 protein, mouse; D051417:Focal Adhesion Kinase 1; D051418:Focal Adhesion Kinase 2; C496051:Ptk2 protein, mouse; C496053:Ptk2b protein, mouse