Phosphorylation of dense-plaque proteins talin and paxillin during tracheal smooth muscle contraction.
Reorganization of cytoskeletal-membrane interactions during contractile stimulation may contribute to the regulation of airway smooth muscle contraction. We investigated the effect of contractile stimulation on the phosphorylation of the actin-membrane attachment proteins talin, vinculin, and paxillin. Stimulation of 32P-labeled canine tracheal smooth muscle strips with acetylcholine (ACh; 10(-3) M) resulted in a rapid 2.6-fold increase in phosphorylation of serine and/or threonine residues, compared with resting levels of 0.22 mol PO4(3-)/mol talin. After stimulation with ACh, phosphorylation of tyrosine residues on paxillin increased approximately threefold. Two-dimensional phosphopeptide mapping of in vivo labeled talin and paxillin indicated phosphorylation on a limited number of sites. Vinculin phosphorylation was undetectable in either resting or ACh-stimulated muscle. We conclude that phosphorylation of talin and paxillin occurs during ACh-stimulated contraction of tracheal smooth muscle and that distinct signaling pathways activate a serine/threonine kinase that phosphorylates talin and a tyrosine kinase that phosphorylates paxillin. The pharmacological activation of airway smooth muscle cells might involve the anchoring of contractile filaments to the membrane.
Pavalko
F M
FM
Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis 46202-5120.
Adam
L P
LP
Wu
M F
MF
Walker
T L
TL
Gunst
S J
SJ
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004285:Dogs; D007163:Immunosorbent Techniques; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology; D051419:Paxillin; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D019000:Phosphotyrosine; D016608:Talin / Q000378:metabolism*; D014132:Trachea / Q000502:physiology*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D016596:Vinculin / Q000378:metabolism
D003598:Cytoskeletal Proteins; D051419:Paxillin; D010750:Phosphoproteins; D016608:Talin; D010769:Phosphothreonine; D016596:Vinculin; D010768:Phosphoserine; D019000:Phosphotyrosine; D014443:Tyrosine; D000109:Acetylcholine