Nesprin-2-epsilon-1 was found in early embryonic cells, while nesprin-2-epsilon-2 was present in heart and other adult tissues, but not skeletal muscle. Expression of nesprin isoforms was highly tissue-dependent. Epsilon isoforms are similar in size and structure to nesprin-1-alpha. Within a complete map of nesprin isoforms, we describe two novel nesprin-2 epsilon isoforms for the first time. We have evaluated the significance of these shorter isoforms using quantitative RT-PCR and western blotting with site-specific monoclonal antibodies. A number of short isoforms lacking the actin-binding domains are produced by internal promotion. Nesprin-1-giant and nesprin-2-giant regulate nuclear positioning by the interaction of their C-terminal KASH domains with nuclear membrane SUN proteins and their N-terminal calponin-homology domains with cytoskeletal actin.
0 kommentar(er)
