Nebulette is a 116.4 kDa protein comprised of 1014 amino acids (See human NEBL sequence features here). 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 (PMID 2037050). 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 (PMID 20951588). 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) (PMID 8581976). Nebulette interacts with actin, tropomyosin and alpha-actinin.[5]
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.[6] Normal expression of nebulette is essential for the assembly and contractile function of myofibrils.[7] 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.[8][9]
Clinical significance
Mutations in the NEBL gene have been associated with dilated cardiomyopathy.[10] Studies in transgenic mice have supported their causative role in endocardial fibroelastosis and DCM.[11]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^{{vcite2 journal | vauthors = Moncman CL, Wang K | title = Functional dissection of nebulette demonstrates actin binding of nebulin-like repeats and Z-line targeting of SH3 and linker domains | journal = Cell Motility and the Cytoskeleton | volume = 44 | issue = 1 | pmid = 10470015 | doi = 10.1002/(SICI)1097-0169(199909)44:1<1::AID-CM1>3.0.CO;2-8 }
^"Nebulette: a 107 kD nebulin-like protein in cardiac muscle". Cell Motility and the Cytoskeleton. 32 (3): 205–25. 1995. doi:10.1002/cm.970320305. PMID8581976. {{cite journal}}: |first2= missing |last2= (help); More than one of author-name-list parameters specified (help)
^Moncman CL, Wang K (Feb 2002). "Targeted disruption of nebulette protein expression alters cardiac myofibril assembly and function". Experimental Cell Research. 273 (2): 204–18. doi:10.1006/excr.2001.5423. PMID11822876.
^Bonzo JR, Norris AA, Esham M, Moncman CL (Nov 2008). "The nebulette repeat domain is necessary for proper maintenance of tropomyosin with the cardiac sarcomere". Experimental Cell Research. 314 (19). doi:10.1016/j.yexcr.2008.09.001. PMID18823973.
^Moncman CL, Wang K (Feb 2002). "Targeted disruption of nebulette protein expression alters cardiac myofibril assembly and function". Experimental Cell Research. 273 (2). doi:10.1006/excr.2001.5423. PMID11822876.
^Arimura T, Nakamura T, Hiroi S, Satoh M, Takahashi M, Ohbuchi N, Ueda K, Nouchi T, Yamaguchi N, Akai J, Matsumori A, Sasayama S, Kimura A (Nov 2000). "Characterization of the human nebulette gene: a polymorphism in an actin-binding motif is associated with nonfamilial idiopathic dilated cardiomyopathy". Human Genetics. 107 (5). PMID11140941.
^Purevjav E, Varela J, Morgado M, Kearney DL, Li H, Taylor MD, Arimura T, Moncman CL, McKenna W, Murphy RT, Labeit S, Vatta M, Bowles NE, Kimura A, Boriek AM, Towbin JA (Oct 2010). "Nebulette mutations are associated with dilated cardiomyopathy and endocardial fibroelastosis". Journal of the American College of Cardiology. 56 (18). doi:10.1016/j.jacc.2010.05.045. PMID20951326.
^Zong NC, Li H, Li H, Lam MP, Jimenez RC, Kim CS, Deng N, Kim AK, Choi JH, Zelaya I, Liem D, Meyer D, Odeberg J, Fang C, Lu HJ, Xu T, Weiss J, Duan H, Uhlen M, Yates JR, Apweiler R, Ge J, Hermjakob H, Ping P (Oct 2013). "Integration of cardiac proteome biology and medicine by a specialized knowledgebase". Circulation Research. 113 (9). doi:10.1161/CIRCRESAHA.113.301151. PMID23965338.
