Anastasi Giuseppe, Cutroneo Giuseppina, Sidoti Antonina, Rinaldi Carmen, Bruschetta Daniele, Rizzo Giuseppina, D'Angelo Rosalia, Tarone Guido, Amato Aldo, Favaloro Angelo
Department of Biomorphology and Biotechnologies, University of Messina, Via Consolare Valeria, 1 IT-98125, Messina, Italy.
J Histochem Cytochem. 2007 Aug;55(8):831-43. doi: 10.1369/jhc.6A7145.2007. Epub 2007 Apr 16.
The sarcoglycan complex (SGC) is a multimember transmembrane complex interacting with other members of the dystrophin-glycoprotein complex (DGC) to provide a mechanosignaling connection from the cytoskeleton to the extracellular matrix. The SGC consists of four proteins (alpha, beta, gamma, and delta). A fifth sarcoglycan subunit, epsilon-sarcoglycan, shows a wider tissue distribution. Recently, a novel sarcoglycan, the zeta-sarcoglycan, has been identified. All reports about the structure of SGC showed a common assumption of a tetrameric arrangement of sarcoglycans. Addressing this issue, our immunofluorescence and molecular results showed, for the first time, that all sarcoglycans are always detectable in all observed samples. Therefore, one intriguing possibility is the existence of a pentameric or hexameric complex considering zeta-sarcoglycan of SGC, which could present a higher or lower expression of a single sarcoglycan in conformity with muscle type--skeletal, cardiac, or smooth--or also in conformity with the origin of smooth muscle.
肌聚糖复合体（SGC）是一种多成员跨膜复合体，与肌营养不良蛋白-糖蛋白复合体（DGC）的其他成员相互作用，以提供从细胞骨架到细胞外基质的机械信号连接。SGC由四种蛋白质（α、β、γ和δ）组成。第五种肌聚糖亚基，即ε-肌聚糖，具有更广泛的组织分布。最近，一种新的肌聚糖，即ζ-肌聚糖，已被鉴定出来。所有关于SGC结构的报道都显示出肌聚糖呈四聚体排列的共同假设。针对这个问题，我们的免疫荧光和分子结果首次表明，在所有观察到的样本中都能检测到所有的肌聚糖。因此，一个有趣的可能性是，考虑到SGC的ζ-肌聚糖，存在五聚体或六聚体复合体，这可能会根据肌肉类型（骨骼肌、心肌或平滑肌）或平滑肌的来源，呈现单个肌聚糖的更高或更低表达。
