Troponina T tipo 2

A troponina T tipo 2 (cardíaca) ou troponina T tipo 2 (TNNT2) é unha proteína que se encontra nos miofilamentos finos musculares do miocardio, que nos humanos está codificada no xene TNNT2 do cromosoma 1.^[1][2] É unha das tres isoformas da troponina T; as outras dúas son TNNT1 e TNNT3. Esta isoforma exprésase no músculo cardíaco adulto. A troponina T únese á tropomiosina situándoa sobre os filamentos de actina do sarcómero muscular tapando os sitios da actina para a unión coa miosina, o que impide a contracción muscular. A troponina é un complexo proteico que regula a contracción muscular formado por tres subunidades, que son as troponinas T, C e I.

PDB 1j1d
Troponina T tipo 2 (cardíaca)
Identificadores
Símbolo	TNNT2
Símbolos alt.	CMH2
Entrez	7139
HUGO	11949
OMIM	191045
RefSeq	NM_000364
UniProt	P45379
Outros datos
Locus	Cr. 1 q32

O xene TNNT2 ten 15 kb e 17 exóns. Orixínanse diversos transcritos deste xene por medio do uso de sitios aceptores alternativos e de splicing alternativo dos exóns 4, 5, 10, e 13.^[3][4] As mutacións neste xene foron asociadas coa miocardiopatía hipertrófica familiar e coa miocardiopatía restritiva^[5] e a miocardiopatía dilatada. As mutacións deste xene poden tamén estar asociadas cunha hipertrofia lixeira ou ausente e unha enfermidade restritiva predominante, con risco de ataque cardíaco súbito mortal.^[5] O avance da miocardiopatía dilatada pode ser máis rápido en pacientes con mutacións no xene TNNT2 que nos que teñen mutacións no xene da cadea pesada da miosina.^[6][7]

Notas

1. Townsend PJ, Farza H, MacGeoch C, Spurr NK, Wade R, Gahlmann R, Yacoub MH, Barton PJ (May 1994). "Human cardiac troponin T: identification of fetal isoforms and assignment of the TNNT2 locus to chromosome 1q". Genomics 21 (2): 311–6. PMID 8088824. doi:10.1006/geno.1994.1271.
2. Gerull B, Osterziel KJ, Witt C, Dietz R, Thierfelder L (1998). "A rapid protocol for cardiac troponin T gene mutation detection in familial hypertrophic cardiomyopathy". Hum. Mutat. 11 (2): 179–82. PMID 9482583. doi:10.1002/(SICI)1098-1004(1998)11:2<179::AID-HUMU12>3.0.CO;2-W.
3. OMIM TROPONIN T2, CARDIAC; TNNT2
4. "Entrez Gene: TNNT2 troponin T type 2 (cardiac)".
5. Revera M, Van der Merwe L, Heradien M, Goosen A, Corfield VA, Brink PA, Moolman-Smook JC (2007). "Long-term follow-up of R403WMYH7 and R92WTNNT2 HCM families: mutations determine left ventricular dimensions but not wall thickness during disease progression". Cardiovasc J Afr 18 (3): 146–53. PMC 4213759. PMID 17612745.
6. Fujino N, Shimizu M, Ino H, Okeie K, Yamaguchi M, Yasuda T, Kokado H, Mabuchi H (May 2001). "Cardiac troponin T Arg92Trp mutation and progression from hypertrophic to dilated cardiomyopathy". Clin Cardiol 24 (5): 397–402. PMID 11346248. doi:10.1002/clc.4960240510.
7. Fujino N, Shimizu M, Ino H, Yamaguchi M, Yasuda T, Nagata M, Konno T, Mabuchi H (January 2002). "A novel mutation Lys273Glu in the cardiac troponin T gene shows high degree of penetrance and transition from hypertrophic to dilated cardiomyopathy". Am. J. Cardiol. 89 (1): 29–33. PMID 11779518. doi:10.1016/S0002-9149(01)02158-0.

Véxase tamén

Bibliografía

• Gomes AV, Barnes JA, Harada K, Potter JD (2005). "Role of troponin T in disease.". Mol. Cell. Biochem. 263 (1–2): 115–29. PMID 15524172. doi:10.1023/B:MCBI.0000041853.20588.a0.
• Noland TA, Raynor RL, Kuo JF (1990). "Identification of sites phosphorylated in bovine cardiac troponin I and troponin T by protein kinase C and comparative substrate activity of synthetic peptides containing the phosphorylation sites". J. Biol. Chem. 264 (34): 20778–85. PMID 2584239.
• Breitbart RE, Nadal-Ginard B (1987). "Developmentally induced, muscle-specific trans factors control the differential splicing of alternative and constitutive troponin T exons". Cell 49 (6): 793–803. PMID 3581171. doi:10.1016/0092-8674(87)90617-9.
• Medford RM, Nguyen HT, Destree AT; et al. (1984). "A novel mechanism of alternative RNA splicing for the developmentally regulated generation of troponin T isoforms from a single gene". Cell 38 (2): 409–21. PMID 6205765. doi:10.1016/0092-8674(84)90496-3.
• Tanokura M, Ohtsuki I (1984). "Interactions among chymotryptic troponin T subfragments, tropomyosin, troponin I and troponin C". J. Biochem. 95 (5): 1417–21. PMID 6746613.
• Pearlstone JR, Smillie LB (1983). "Effects of troponin-I plus-C on the binding of troponin-T and its fragments to alpha-tropomyosin. Ca2+ sensitivity and cooperativity". J. Biol. Chem. 258 (4): 2534–42. PMID 6822572.
• Kovalyov LI, Shishkin SS, Efimochkin AS; et al. (1996). "The major protein expression profile and two-dimensional protein database of human heart". Electrophoresis 16 (7): 1160–9. PMID 7498159. doi:10.1002/elps.11501601192.
• Anderson PA, Greig A, Mark TM; et al. (1995). "Molecular basis of human cardiac troponin T isoforms expressed in the developing, adult, and failing heart". Circ. Res. 76 (4): 681–6. PMID 7534662. doi:10.1161/01.res.76.4.681.
• Mesnard L, Logeart D, Taviaux S; et al. (1995). "Human cardiac troponin T: cloning and expression of new isoforms in the normal and failing heart". Circ. Res. 76 (4): 687–92. PMID 7895342. doi:10.1161/01.res.76.4.687.
• Watkins H, McKenna WJ, Thierfelder L; et al. (1995). "Mutations in the genes for cardiac troponin T and alpha-tropomyosin in hypertrophic cardiomyopathy". N. Engl. J. Med. 332 (16): 1058–64. PMID 7898523. doi:10.1056/NEJM199504203321603.
• Watkins H, MacRae C, Thierfelder L; et al. (1995). "A disease locus for familial hypertrophic cardiomyopathy maps to chromosome 1q3". Nat. Genet. 3 (4): 333–7. PMID 7981753. doi:10.1038/ng0493-333.
• Townsend PJ, Farza H, MacGeoch C; et al. (1994). "Human cardiac troponin T: identification of fetal isoforms and assignment of the TNNT2 locus to chromosome 1q". Genomics 21 (2): 311–6. PMID 8088824. doi:10.1006/geno.1994.1271.
• Thierfelder L, Watkins H, MacRae C; et al. (1994). "Alpha-tropomyosin and cardiac troponin T mutations cause familial hypertrophic cardiomyopathy: a disease of the sarcomere". Cell 77 (5): 701–12. PMID 8205619. doi:10.1016/0092-8674(94)90054-X.
• Mesnard L, Samson F, Espinasse I; et al. (1993). "Molecular cloning and developmental expression of human cardiac troponin T". FEBS Lett. 328 (1–2): 139–44. PMID 8344420. doi:10.1016/0014-5793(93)80981-Y.
• Durand JB, Bachinski LL, Bieling LC; et al. (1996). "Localization of a gene responsible for familial dilated cardiomyopathy to chromosome 1q32". Circulation 92 (12): 3387–9. PMID 8521556. doi:10.1161/01.cir.92.12.3387.
• Townsend PJ, Barton PJ, Yacoub MH, Farza H (1996). "Molecular cloning of human cardiac troponin T isoforms: expression in developing and failing heart". J. Mol. Cell. Cardiol. 27 (10): 2223–36. PMID 8576938. doi:10.1016/S0022-2828(95)91587-7.
• Jideama NM, Noland TA, Raynor RL; et al. (1996). "Phosphorylation specificities of protein kinase C isozymes for bovine cardiac troponin I and troponin T and sites within these proteins and regulation of myofilament properties". J. Biol. Chem. 271 (38): 23277–83. PMID 8798526. doi:10.1074/jbc.271.38.23277.
• Forissier JF, Carrier L, Farza H; et al. (1997). "Codon 102 of the cardiac troponin T gene is a putative hot spot for mutations in familial hypertrophic cardiomyopathy". Circulation 94 (12): 3069–73. PMID 8989109. doi:10.1161/01.cir.94.12.3069.
• Moolman JC, Corfield VA, Posen B; et al. (1997). "Sudden death due to troponin T mutations". J. Am. Coll. Cardiol. 29 (3): 549–55. PMID 9060892. doi:10.1016/S0735-1097(96)00530-X.
• Nakajima-Taniguchi C, Matsui H, Fujio Y; et al. (1997). "Novel missense mutation in cardiac troponin T gene found in Japanese patient with hypertrophic cardiomyopathy". J. Mol. Cell. Cardiol. 29 (2): 839–43. PMID 9140840. doi:10.1006/jmcc.1996.0322.

Ligazóns externas

• GeneReviews/NIH/NCBI/UW entrada sobre a cardiopatía hipertrófica familiar