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KMID : 0578319960060060737
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Molecules and Cells
1996 Volume.6 No. 6 p.737 ~ p.745
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Localization of α3 Integrin in the Sarcomere during Cardiac Myocyte Development in Vitro
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Yoon, Sung Won
Gu, Hyunmin/Kwon, Hyockman/Song, Woo Keun/Kang, Man-Sik
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Abstract
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Using double immunofluorescence microscopy, the cellular distribution of extracellular matrix (ECM) components and integrin alpha chains during neonatal myocyte development in culture
has been demonstrated. Cultured neonatal myocytes appeared to express a variety of integrin alpha chains, such as α1, α3, and α7. The α1 and α3 integrins were responsible for the interaction with collagen. The α7 integrin staining was restricted to myocytes. Laminin was selectively found in myocytes stained by anti-desmin antibody, whereas the distribution of fibronectin was specific for fibroblasts. The α5 integrin staining was prominent in fibroblasts but not in myocytes. These observations demonstrated that the expression of integrin alpha chains was closely associated with the distribution of ECM components on cell sufaces. In addition, the cellular localization of α3 integrin was dramatically changed from a diffuse pattern into a sarcomeric banding pattern during development while other alpha chains appeared in a diffuse staining pattern. The α3 integrin
appeared to be localized in the sarcolemma region adjacent to the Z-band. α-actinin, a component of the Z-band, was also localized in the same region. Double immunostaining revealed that the integration of α3 integrin into the Z-band was next to that of α-actinin and myosin heavy chain but prior to that of desmin, suggesting that α3 integrin was integrated into a pre-existing myofibrillar structure but did not participate in initiat assembly of myofibrillar proteins. The α3 integrin seems to be associated with β1 integrin and to function as a collagen receptor. Thus, the myofibril-collagen fibril linkages mediated by α3β1 integrin receptor may play an essential role in the stabilization of myofibril assembly.
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KEYWORD
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