title: Vascular smooth muscle cell motility is mediated by a physical and functional interaction of Ca2+/calmodulin-dependent protein kinase IIδ2 and Fyn.
abstract: In vascular smooth muscle (VSM) cells, Ca(2+)/calmodulin-dependent protein kinase IIδ2 (CaMKIIδ2) activates non-receptor tyrosine kinases and EGF receptor, with a Src family kinase as a required intermediate. siRNA-mediated suppression of Fyn, a Src family kinase, inhibited VSM cell motility. Simultaneous suppression of both Fyn and CaMKIIδ2 was non-additive, suggesting coordinated regulation of cell motility. Confocal immunofluorescence microscopy indicated that CaMKIIδ2 and Fyn selectively (compared with Src) co-localized with the Golgi in quiescent cultured VSM cells. Stimulation with PDGF resulted in a rapid (<5 min) partial redistribution and co-localization of both kinases in peripheral membrane regions. Furthermore, CaMKIIδ2 and Fyn selectively (compared with Src) co-immunoprecipitated, suggesting a physical interaction in a signaling complex. Stimulation of VSM cells with ionomycin, a calcium ionophore, resulted in activation of CaMKIIδ2 and Fyn and disruption of the complex. Pretreatment with KN-93, a pharmacological inhibitor of CaMKII, prevented activation-dependent disruption of CaMKIIδ2 and Fyn, implicating CaMKIIδ2 as an upstream mediator of Fyn. Overexpression of constitutively active CaMKII resulted in the dephosphorylation of Fyn at Tyr-527, which is required for Fyn activation. Taken together, these data demonstrate a dynamic interaction between CaMKIIδ2 and Fyn in VSM cells and indicate a mechanism by which CaMKIIδ2 and Fyn may coordinately regulate VSM cell motility.
authors.affiliation: From the Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208.
authors.forename: Roman
authors.initials: R
authors.lastname: Ginnan
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Zou
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Pfleiderer
authors.forename: Melissa Z
authors.initials: MZ
authors.lastname: Mercure
authors.forename: Margarida
authors.initials: M
authors.lastname: Barroso
authors.forename: Harold A
authors.initials: HA
authors.lastname: Singer
mesh_terms: D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D015151:Immunoblotting; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D011485:Protein Binding; D051076:Proto-Oncogene Proteins c-fyn / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D034622:RNA Interference; D051381:Rats; D017207:Rats, Sprague-Dawley; D019061:src-Family Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: C412373:AG 1879; D011743:Pyrimidines; C494961:Fyn protein, rat; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2
keywords: Calcium Signaling; Calcium/Calmodulin-dependent Protein Kinase (CaMK); Cell Migration; Protein Complexes; Protein Kinases; Vascular Smooth Muscle Cells