Bergdahl Andreas, Swärd Karl
Department of Physiological Sciences, Lund University, Biomedical Centre, Sweden.
Can J Physiol Pharmacol. 2004 May;82(5):289-99. doi: 10.1139/y04-033.
Caveolae are flask-shaped invaginations in the membrane that depend on the contents of cholesterol and on the structural protein caveolin. The organisation of caveolae in parallel strands between dense bands in smooth muscle is arguably unique. It is increasingly recognised, bolstered in large part by recent studies in caveolae deficient animals, that caveolae sequester and regulate a variety of signalling intermediaries. The role of caveolae in smooth muscle signal transduction, as inferred from studies on transgenic animals and in vitro approaches, is the topic of the current review. Both G-protein coupled receptors and tyrosine kinase receptors are believed to cluster in caveolae, and the exciting possibility that caveolae provide a platform for interactions between the sarcoplasmic reticulum and plasmalemmal ion channels is emerging. Moreover, messengers involved in Ca2+ sensitization of myosin phosphorylation and contraction may depend on caveolae or caveolin. Caveolae thus appear to constitute an important signalling domain that plays a role not only in regulation of smooth muscle tone, but also in proliferation, such as seen in neointima formation and atherosclerosis.
小窝是细胞膜中呈烧瓶状的内陷结构，其依赖于胆固醇含量和结构蛋白小窝蛋白。平滑肌致密带之间平行排列的小窝结构可以说是独一无二的。越来越多的研究表明，在很大程度上得益于对小窝缺陷动物的最新研究，小窝能隔离并调节多种信号中间体。从对转基因动物和体外实验方法的研究推断，小窝在平滑肌信号转导中的作用是当前综述的主题。人们认为G蛋白偶联受体和酪氨酸激酶受体都聚集在小窝中，并且小窝为肌浆网和质膜离子通道之间的相互作用提供平台这一令人兴奋的可能性正在显现。此外，参与肌球蛋白磷酸化和收缩的Ca2+致敏的信使分子可能依赖于小窝或小窝蛋白。因此，小窝似乎构成了一个重要的信号域，不仅在调节平滑肌张力中起作用，而且在诸如新生内膜形成和动脉粥样硬化等增殖过程中也起作用。
