Pavalko F M, Adam L P, Wu M F, Walker T L, Gunst S J
Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis 46202-5120.
Am J Physiol. 1995 Mar;268(3 Pt 1):C563-71. 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.
收缩刺激期间细胞骨架-膜相互作用的重组可能有助于气道平滑肌收缩的调节。我们研究了收缩刺激对肌动蛋白-膜附着蛋白踝蛋白、纽蛋白和桩蛋白磷酸化的影响。用乙酰胆碱（ACh；10⁻³ M）刺激³²P标记的犬气管平滑肌条，与静息水平的0.22 mol PO₄³⁻/mol踝蛋白相比，丝氨酸和/或苏氨酸残基的磷酸化迅速增加了2.6倍。用ACh刺激后，桩蛋白上酪氨酸残基的磷酸化增加了约三倍。对体内标记的踝蛋白和桩蛋白进行二维磷酸肽图谱分析表明，磷酸化发生在有限数量的位点上。在静息或ACh刺激的肌肉中均未检测到纽蛋白磷酸化。我们得出结论，在ACh刺激的气管平滑肌收缩过程中发生了踝蛋白和桩蛋白的磷酸化，并且不同的信号通路激活了使踝蛋白磷酸化的丝氨酸/苏氨酸激酶和使桩蛋白磷酸化的酪氨酸激酶。气道平滑肌细胞的药理学激活可能涉及收缩细丝与膜的锚定。
