Distinct Effects of Contraction Agonists on the Phosphorylation State of Cofilin in Pulmonary Artery Smooth Muscle
Figure 2
Norepinephrine-(NE) induced contraction and CF phosphorylation of PA rings were attenuated by the Rho-kinase inhibitor Y-27632. Freshly dissected canine PA rings were incubated with 1 M NE without (panel (a)) or after 1-hour preincubation with Y-27632 (1 M panel (b)). Strips were snap-frozen at the maximal contraction amplitude and homogenized. Total protein was resolved by SDS-PAGE and transferred onto nitrocellulose membranes. CF and P-CF were assayed by immunoblotting (panel (c)). Immunoreactive P-CF band densities (panel (c), top inset) were normalized to immunoreactive CF bands (panel (c), bottom inset), and treatment-induced changes in P-CF/CF ratio were expressed as percent of unstimulated controls (Ctr, bar graph). Panel (d): Schematic of signal transduction leading to phosphorylation of cofilin and documented CF-mediated cell functional responses. Abbreviations: Agonist R, agonist receptor; Rho, Rho GTPases; MLC, myosin light chain; LIMK, LIM kinase, PPh, protein phosphatases, MCLF, microcystin LF. Mean SD, (*) compared to untreated controls, .
