Kogo Hiroshi, Ito Shin-ya, Moritoki Yoshinobu, Kurahashi Hiroki, Fujimoto Toyoshi
Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, 466-8550, Japan.
Cell Tissue Res. 2006 May;324(2):291-300. doi: 10.1007/s00441-005-0130-z. Epub 2006 Jan 28.
Expression of caveolin-1 and -3 in mouse smooth muscle cells in vivo was examined by immunohistochemistry. Caveolin-1 was detected in almost all smooth muscles examined, except for the pupillary dilator muscle, whereas caveolin-3 was present only in smooth muscles of some specific tissues. In the eye, the pupillary sphincter muscle was intensely positive for caveolin-3, whereas the ciliary muscle and pupillary dilator muscle were negative. In the gastrointestinal tract, caveolin-3 was detected in the inner circular layer, but not in the outer longitudinal layer. Vascular smooth muscle cells of the resistance-sized artery in the uterus and corpus cavernosum were intensely positive for caveolin-3, whereas those of the aorta were only weakly positive and those of the vena cava were negative. Caveolin-3 was also detected in smooth muscle cells of the urinary bladder, ureter, prostatic vas deferens, and seminal vesicle. The different levels of caveolin-3 expression among various smooth muscle tissues were confirmed by Western blot analysis. Even within the same muscle, the relative expression levels of caveolin-1 and -3 were variable among neighboring cells, suggesting distinct fine regulation of expression of these two caveolins. Moreover, even in the same cell, caveolin-1 and -3 showed different distributions. These results indicate that the two caveolins form distinct caveolae in smooth muscles, and that caveolin-1 and -3 serve different functions. Their differential expression may therefore be related to the functional diversity of smooth muscles.
通过免疫组织化学法检测了小窝蛋白-1和-3在小鼠体内平滑肌细胞中的表达情况。除瞳孔开大肌外,在几乎所有检测的平滑肌中均检测到小窝蛋白-1,而小窝蛋白-3仅存在于某些特定组织的平滑肌中。在眼睛中,瞳孔括约肌小窝蛋白-3呈强阳性,而睫状肌和瞳孔开大肌呈阴性。在胃肠道中,小窝蛋白-3在内环层中被检测到,但在外纵层中未被检测到。子宫和海绵体中阻力动脉的血管平滑肌细胞小窝蛋白-3呈强阳性,而主动脉的血管平滑肌细胞仅呈弱阳性,腔静脉的血管平滑肌细胞呈阴性。在膀胱、输尿管、前列腺输精管和精囊的平滑肌细胞中也检测到了小窝蛋白-3。通过蛋白质印迹分析证实了不同平滑肌组织中小窝蛋白-3表达水平的差异。即使在同一肌肉内,相邻细胞中小窝蛋白-1和-3的相对表达水平也存在差异,这表明这两种小窝蛋白的表达存在明显的精细调控。此外,即使在同一细胞中,小窝蛋白-1和-3也表现出不同的分布。这些结果表明,这两种小窝蛋白在平滑肌中形成不同的小窝,并且小窝蛋白-1和-3发挥不同的功能。因此,它们的差异表达可能与平滑肌的功能多样性有关。