Zeidan Asad, Swärd Karl, Nordström Ina, Ekblad Eva, Zhang Janet C L, Parmacek Michael S, Hellstrand Per
Department of Physiological Sciences, Lund University, Biomedical Centre, BMC F12, SE-221 84 Lund, Sweden.
FEBS Lett. 2004 Mar 26;562(1-3):141-6. doi: 10.1016/S0014-5793(04)00220-0.
The actin-binding protein SM22alpha marks contractile differentiation in smooth muscle, but its function is unknown. We tested its role in arterial contractility and stretch-sensitive vascular protein synthesis. Active stress in depolarised mesenteric resistance arteries and portal veins was reduced by 40% in SM22alpha(-/-) mice. Passive and active arterial circumference-force relationships were shifted leftwards, whereas alpha(1)-adrenergic responses were increased. Actin contents were 10-25% lower in vessels from SM22alpha(-/-) mice, but protein composition was otherwise similar. Synthesis of SM22alpha, calponin and alpha-actin, but not beta-actin, was sensitive to stretch. Ablation of SM22alpha did not affect stretch sensitivity of any of these proteins. Thus, SM22alpha plays a role in contractility, possibly by affecting actin filament organisation.
肌动蛋白结合蛋白SM22α标志着平滑肌的收缩分化，但其功能尚不清楚。我们测试了它在动脉收缩性和拉伸敏感的血管蛋白合成中的作用。在SM22α基因敲除小鼠中，去极化肠系膜阻力动脉和门静脉的主动张力降低了40%。动脉被动和主动周长-力关系向左移位，而α1-肾上腺素能反应增强。来自SM22α基因敲除小鼠的血管中肌动蛋白含量低10%-25%，但蛋白质组成在其他方面相似。SM22α、钙调蛋白和α-肌动蛋白（而非β-肌动蛋白）的合成对拉伸敏感。敲除SM22α并不影响这些蛋白质中任何一种的拉伸敏感性。因此，SM22α可能通过影响肌动蛋白丝的组织而在收缩性中发挥作用。
