Structure
Nebulette is a 116.4 kDa protein composed of 1014 amino acids.[5][6] As a member of the nebulin family of proteins, nebulette is characterized by 35 amino acid stretches of ‘‘nebulin repeats’’, which are actin binding domains containing a conserved SDxxYK motif.[7] Like nebulin, nebulette has an acidic region with unknown structure at its N-terminus, and a serine-rich region adjacent to an SH3 domain at its C-terminus.[8] Though nebulette shares structural features with nebulin, nebulin is expressed preferentially in skeletal muscle and has an enormous size (600-900 kDa), while nebulette is expressed in cardiac muscle at Z-disc regions and is significantly smaller (roughly 1/6 of the size).[9] Nebulette interacts with actin, tropomyosin, alpha-actinin.[10] Xin, and XIRP2.[11]
Function
Nebulette was identified in 1995 by Moncman and Wang using primary cultures of chicken embryonic cardiomyocytes by immunoprecipitations with certain anti-nebulin monoclonal antibodies.[12] Normal expression of nebulette is essential for the assembly and contractile function of myofibrils.[13] Specifically, nebulette appears to regulate the stability and length of actin thin filaments, as well as beating frequencies of cardiomyocytes; reduction of full-length nebulette protein in cardiomyocytes resulted in reduced thin filament lengths, depressed beating frequencies and loss of thin filament regulatory proteins troponin I and tropomyosin.[14][15]
Clinical significance
Further reading
References
External links
