Proteína quinase activada por mitóxeno: Diferenzas entre revisións

 

[[Ficheiro:MAPK-evolutionary-tree.png|miniatura|Orixes evolutivas das proteína quinases activadas por mitóxeno (MAPK)<ref name="pmid23382384"/><ref name="pmid22046431">{{cite journal |vauthors=Li M, Liu J, Zhang C |title=Evolutionary history of the vertebrate mitogen activated protein kinases family |journal=PLoS ONE |volume=6 |issue=10 |pages=e26999 |year=2011 |pmid=22046431 |pmc=3202601 |doi=10.1371/journal.pone.0026999 }}</ref>]]

Members of the MAPK family can be found in every eukaryotic organism examined so far. In particular, both classical and atypical MAP kinases can be traced back to the root of the radiation of major eukaryotic groups. Terrestrial plants contain four groups of classical MAPKs (MAPK-A, MAPK-B, MAPK-C and MAPK-D) that are involved in response to myriads of abiotic stresses.<ref name="pmid12119167">{{cite journal | author = MAPK Group | title = Mitogen-activated protein kinase cascades in plants: a new nomenclature | journal = Trends in Plant Science | volume = 7 | issue = 7 | pages = 301–8 | date = Jul 2002 | pmid = 12119167 | doi = 10.1016/S1360-1385(02)02302-6 }}</ref> However, none of these groups can be directly equated to the clusters of classical MAPKs found in [[opisthokont]]s (fungi and animals). In the latter, the major subgroups of classical MAPKs form the ERK/Fus3-like branch (that is further sub-divided in [[metazoan]]s into ERK1/2 and ERK5 subgroups), and the p38/Hog1-like kinases (that has also split into the p38 and the JNK subgroups in multicellular animals).<ref name="pmid10552038">{{cite journal | vauthors = Caffrey DR, O'Neill LA, Shields DC | title = The evolution of the MAP kinase pathways: coduplication of interacting proteins leads to new signaling cascades | journal = Journal of Molecular Evolution | volume = 49 | issue = 5 | pages = 567–82 | date = Nov 1999 | pmid = 10552038 | doi = 10.1007/PL00006578 }}</ref> In addition, there are several MAPKs in both fungi and animals, whose origins are less clear, either due to high divergence (e.g. NLK), or due to possibly being an early offshoot to the entire MAPK family (ERK3, ERK4, ERK7). In vertebrates, due to the twin whole genome duplications after the cephalochordate/vertebrate split,<ref name="pmid18563158">{{cite journal | vauthors = Putnam NH, Butts T, Ferrier DE, Furlong RF, Hellsten U, Kawashima T, Robinson-Rechavi M, Shoguchi E, Terry A, Yu JK, Benito-Gutiérrez EL, Dubchak I, Garcia-Fernàndez J, Gibson-Brown JJ, Grigoriev IV, Horton AC, de Jong PJ, Jurka J, Kapitonov VV, Kohara Y, Kuroki Y, Lindquist E, Lucas S, Osoegawa K, Pennacchio LA, Salamov AA, Satou Y, Sauka-Spengler T, Schmutz J, Shin-I T, Toyoda A, Bronner-Fraser M, Fujiyama A, Holland LZ, Holland PW, Satoh N, Rokhsar DS | display-authors = 6 | title = The amphioxus genome and the evolution of the chordate karyotype | journal = Nature | volume = 453 | issue = 7198 | pages = 1064–71 | date = Jun 2008 | pmid = 18563158 | doi = 10.1038/nature06967 }}</ref> there are several paralogs in every group. Thus ERK1 and ERK2 both correspond to the ''[[Drosophila]]'' kinase ''rolled'', JNK1, JNK2 and JNK3 are all orthologous to the gene ''basket'' in ''Drosophila''. Although among the p38 group, p38 alpha and beta are clearly paralogous pairs, and so are p38 gamma and delta in vertebrates, the timing of the base split is less clear, given that many metazoans already possess multiple p38 homologs (there are three p38-type kinases in ''Drosophila'', ''Mpk2''(''p38a''), ''p38b'' and ''p38c''). The single ERK5 protein appears to fill a very specialized role (essential for vascular development in vertebrates) wherever it is present. This lineage has been deleted in [[protostome]]s, together with its upstream pathway components (MEKK2/3, MKK5), although they are clearly present in [[cnidaria]]ns, [[sponge]]s and even in certain unicellular organisms (e.g. the [[choanoflagellate]] ''Monosiga brevicollis'') closely related to the origins of multicellular animals.<ref name="pmid18273011">{{cite journal | vauthors = King N, Westbrook MJ, Young SL, Kuo A, Abedin M, Chapman J, Fairclough S, Hellsten U, Isogai Y, Letunic I, Marr M, Pincus D, Putnam N, Rokas A, Wright KJ, Zuzow R, Dirks W, Good M, Goodstein D, Lemons D, Li W, Lyons JB, Morris A, Nichols S, Richter DJ, Salamov A, Sequencing JG, Bork P, Lim WA, Manning G, Miller WT, McGinnis W, Shapiro H, Tjian R, Grigoriev IV, Rokhsar D | display-authors = 6 | title = The genome of the choanoflagellate Monosiga brevicollis and the origin of metazoans | journal = Nature | volume = 451 | issue = 7180 | pages = 783–8 | date = Feb 2008 | pmid = 18273011 | pmc = 2562698 | doi = 10.1038/nature06617 }}</ref>