As timopoetinas, timopoietinas ou isoformas beta/gamma do polipéptido 2 asociado ás laminas[1] son unhas proteínas codificadas polo xeneTMPO nos humanos.[2][3]
A timopoetina foi illada inicialmente do timo bovino e déuselle primeiro o nome de timina, que foi cambiado a timopoetina, para non confundila coa base nitroxenadatimina[4].
Á timopoetina atribúeselle unha acción hormonal, que induce a diferenciación dos timocitos a partir das súas células precursoras [5].
O xene da timopoetina (TMPO) codifica tres ARNm, resultado dun splicing alternativo, que orixinan tres proteínas, de 75 kDa (alfa), 51 kDa (beta) e 39 kDa (gamma), que son expresadas en todas as células. O xene TMPO humano atópase na banda 12q22 do cromosoma 22 e consta de oito exóns. O TMPO alfa está presente e difusamente expresado no núcleo celular, e os TMPO beta e gamma están localizados na membrana nuclear. O TMPO beta é un homólogo humano da proteína murina LAP2 (polipéptido 2 asociado á lamina). O LAP2 desempeña un papel na regulación da arquitectura nuclear ao unir a proteína lamina B1 cos cromosomas e intervir na formación da lámina nuclear. Esta interacción está regulada por fosforilación durante a mitose. Dada a localización nuclear das tres isoformas de TMPO, é improbable que estas proteínas xoguen un papel na indución do CD90 no timo, como se suxerira.
↑Gideon Goldstein. The isolation of thymopoietin (thymin). Annals of the New York Academy of Sciences. Volume 249, Thymus Factors in Immunity pages 177–185, February 1975 [1]
↑J J Twomey, G Goldstein, V M Lewis, P M Bealmear, R A Good.
Bioassay determinations of thymopoietin and thymic hormone levels in human plasma. Proceedings of the National Academy of Science of USA. June 1, 1977 vol. 74 no. 6 2541-2545. [2]
↑Furukawa, K (1999). "LAP2 binding protein 1 (L2BP1/BAF) is a candidate mediator of LAP2-chromatin interaction". J. Cell. Sci. (ENGLAND) 112 (15): 2485–92. ISSN0021-9533. PMID10393804.
↑Martins, S B; Eide T, Steen R L, Jahnsen T, Skålhegg B S, Collas P (2000). "HA95 is a protein of the chromatin and nuclear matrix regulating nuclear envelope dynamics". J. Cell. Sci. (ENGLAND) 113 (21): 3703–13. ISSN0021-9533. PMID11034899.
↑Foisner, R; Gerace L (1993). "Integral membrane proteins of the nuclear envelope interact with lamins and chromosomes, and binding is modulated by mitotic phosphorylation". Cell (UNITED STATES) 73 (7): 1267–79. ISSN0092-8674. PMID8324822. doi:10.1016/0092-8674(93)90355-T.
Harris CA, Andryuk PJ, Cline SW, Mathew S, Siekierka JJ, Goldstein G (1995). "Structure and mapping of the human thymopoietin (TMPO) gene and relationship of human TMPO beta to rat lamin-associated polypeptide 2". Genomics28 (2): 198–205. PMID8530026. doi:10.1006/geno.1995.1131.
Dechat T, Vlcek S, Foisner R (2000). "Review: lamina-associated polypeptide 2 isoforms and related proteins in cell cycle-dependent nuclear structure dynamics.". J. Struct. Biol.129 (2-3): 335–45. PMID10806084. doi:10.1006/jsbi.2000.4212.
Heavner GA, Audhya T, Goldstein G (1990). "Peptide analogs of thymopentin distinguish distinct thymopoietin receptor specificities on two human T cell lines.". Regul. Pept.27 (2): 257–62. PMID2158125. doi:10.1016/0167-0115(90)90044-W.
Fuccello A, Audhya T, Talle MA, Goldstein G (1984). "Immunoassay for bovine serum thymopoietin: discrimination from splenin by monoclonal antibodies.". Arch. Biochem. Biophys.228 (1): 292–8. PMID6364989. doi:10.1016/0003-9861(84)90070-5.
Hara H, Hayashi K, Ohta K; et al. (1995). "A new thymopoietin precursor gene from human thymus.". Biochem. Mol. Biol. Int.34 (5): 927–33. PMID7703909.
Harris CA, Andryuk PJ, Cline SW; et al. (1996). "Structure and mapping of the human thymopoietin (TMPO) gene and relationship of human TMPO beta to rat lamin-associated polypeptide 2.". Genomics28 (2): 198–205. PMID8530026. doi:10.1006/geno.1995.1131.
Andersson B, Wentland MA, Ricafrente JY; et al. (1996). "A "double adaptor" method for improved shotgun library construction.". Anal. Biochem.236 (1): 107–13. PMID8619474. doi:10.1006/abio.1996.0138.
Berger R, Theodor L, Shoham J; et al. (1996). "The characterization and localization of the mouse thymopoietin/lamina-associated polypeptide 2 gene and its alternatively spliced products.". Genome Res.6 (5): 361–70. PMID8743987. doi:10.1101/gr.6.5.361.
Furukawa K, Fritze CE, Gerace L (1998). "The major nuclear envelope targeting domain of LAP2 coincides with its lamin binding region but is distinct from its chromatin interaction domain.". J. Biol. Chem.273 (7): 4213–9. PMID9461618. doi:10.1074/jbc.273.7.4213.
Furukawa K, Kondo T (1998). "Identification of the lamina-associated-polypeptide-2-binding domain of B-type lamin.". Eur. J. Biochem.251 (3): 729–33. PMID9490046. doi:10.1046/j.1432-1327.1998.2510729.x.
Furukawa K (1999). "LAP2 binding protein 1 (L2BP1/BAF) is a candidate mediator of LAP2-chromatin interaction.". J. Cell. Sci.112 (15): 2485–92. PMID10393804.
Martins SB, Eide T, Steen RL; et al. (2001). "HA95 is a protein of the chromatin and nuclear matrix regulating nuclear envelope dynamics.". J. Cell. Sci.113 (21): 3703–13. PMID11034899.