title: Interaction between src family kinases and rho-kinase in agonist-induced Ca2+-sensitization of rat pulmonary artery.
abstract: OBJECTIVE
  We investigated the role of src family kinases (srcFK) in agonist-mediated Ca2+-sensitization in pulmonary artery and whether this involves interaction with the rho/rho-kinase pathway.
  
  
  RESULTS
  Intra-pulmonary arteries (IPAs) and cultured pulmonary artery smooth muscle cells (PASMC) were obtained from rat. Expression of srcFK was determined at the mRNA and protein levels. Ca2+-sensitization was induced by prostaglandin F(2 alpha) (PGF(2 alpha)) in alpha-toxin-permeabilized IPAs. Phosphorylation of the regulatory subunit of myosin phosphatase (MYPT-1) and of myosin light-chain-20 (MLC20) and translocation of rho-kinase in response to PGF(2 alpha) were also determined. Nine srcFK were expressed at the mRNA level, including src, fyn, and yes, and PGF(2 alpha) enhanced phosphorylation of three srcFK proteins at tyr-416. In alpha-toxin-permeabilized IPAs, PGF(2 alpha) enhanced the Ca2+-induced contraction (pCa 6.9) approximately three-fold. This enhancement was inhibited by the srcFK blockers SU6656 and PP2 and by the rho-kinase inhibitor Y27632. Y27632, but not SU6656 or PP2, also inhibited the underlying pCa 6.9 contraction. PGF(2 alpha) enhanced phosphorylation of MYPT-1 at thr-697 and thr-855 and of MLC20 at ser-19. This enhancement, but not the underlying basal phosphorylation, was inhibited by SU6656. Y27632 suppressed both basal and PGF(2 alpha)-mediated phosphorylation. The effects of SU6656 and Y27632, on both contraction and MYPT-1 and MLC20 phosphorylation, were not additive. PGF(2 alpha) triggered translocation of rho-kinase in PASMC, and this was inhibited by SU6656.
  
  
  CONCLUSIONS
  srcFK are activated by PGF(2 alpha) in the rat pulmonary artery and may contribute to Ca2+-sensitization and contraction via rho-kinase translocation and phosphorylation of MYPT-1.
authors.affiliation: Department of Asthma, Allergy and Respiratory Science, School of Medicine, King's College London, Room 3.20, Franklin Wilkins Building, Stamford Street, London SE1 9NH, UK. greg.knock@kcl.ac.uk
authors.forename: Greg A
authors.initials: GA
authors.lastname: Knock
authors.forename: Yasin
authors.initials: Y
authors.lastname: Shaifta
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Snetkov
authors.forename: Benjamin
authors.initials: B
authors.lastname: Vowles
authors.forename: Svetlana
authors.initials: S
authors.lastname: Drndarski
authors.forename: Jeremy P T
authors.initials: JP
authors.lastname: Ward
authors.forename: Philip I
authors.initials: PI
authors.lastname: Aaronson
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D015237:Dinoprost / Q000494:pharmacology; D008297:Male; D018994:Myosin Light Chains / Q000378:metabolism; D010766:Phosphorylation; D054645:Protein Phosphatase 1 / Q000378:metabolism; D011651:Pulmonary Artery / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014443:Tyrosine / Q000378:metabolism; D054460:rho-Associated Kinases / Q000502:physiology*; D019061:src-Family Kinases / Q000502:physiology*
chemical_list: D018994:Myosin Light Chains; D014443:Tyrosine; D015237:Dinoprost; D019061:src-Family Kinases; D054460:rho-Associated Kinases; C499850:Ppp1r12a protein, rat; D054645:Protein Phosphatase 1; D002118:Calcium