Phosphorylation of dense-plaque proteins talin and paxillin during tracheal smooth muscle contraction

• Published in: The American journal of physiology Vol. 268; no. 3 Pt 1; p. C563
• Main Authors: Pavalko, F M, Adam, L P, Wu, M F, Walker, T L, Gunst, S J
• Format: Journal Article
• Language: English
• Published: United States 01.03.1995
• Subjects: Acetylcholine - pharmacology; Animals; Binding Sites; Cytoskeletal Proteins - metabolism; Dogs; Immunosorbent Techniques; Muscle Contraction - drug effects; Muscle Contraction - physiology; Muscle, Smooth - physiology; Paxillin; Phosphoproteins - metabolism; Phosphorylation; Phosphoserine - metabolism; Phosphothreonine - metabolism; Phosphotyrosine; Talin - metabolism; Trachea - physiology; Tyrosine - analogs & derivatives; Tyrosine - metabolism; Vinculin - metabolism
• ISSN: 0002-9513; 2163-5773
• DOI: 10.1152/ajpcell.1995.268.3.c563

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.