Revisión como estaba o 11 de xaneiro de 2019 ás 22:58 editar Miguelferig (conversa \| contribucións) 241.989 edicións →‎Estrutura ← Edición máis vella		Revisión como estaba o 11 de xaneiro de 2019 ás 23:23 editar desfacer Miguelferig (conversa \| contribucións) 241.989 edicións →‎N-terminal Edición máis nova →
Liña 111: === N-terminal === <!--▼ The [[N-terminus\|N-terminal]] heparin-binding domain of TSP1, when isolated as a 25[[kDa]] fragment, has been shown to be a potent inducer of cell migration at high concentrations. However, when the heparin-binding domain of TSP1 is cleaved, the remaining anti-angiogenic domains have been shown to have decreased anti-angiogenic activity at low concentrations where increased [[endothelial cell]] (EC) migration occurs. This may be explained in part by the ability of the heparin-binding domain to mediate attachment of TSP1 to cells, allowing the other domains to exert their effects. The separate roles that the heparin-binding region of TSP1 plays at high versus low concentrations may be in part responsible for regulating the two-faced nature of TSP1 and giving it a reputation of being both a positive and negative regulator of angiogenesis.<ref name="pmid7686555">{{cite journal \| vauthors = Tolsma SS, Volpert OV, Good DJ, Frazier WA, Polverini PJ, Bouck N \| title = Peptides derived from two separate domains of the matrix protein thrombospondin-1 have anti-angiogenic activity \| journal = The Journal of Cell Biology \| volume = 122 \| issue = 2 \| pages = 497–511 \| date = Jul 1993 \| pmid = 7686555 \| pmc = 2119646 \| doi = 10.1083/jcb.122.2.497 }}</ref> O dominio de unión á heparina N-terminal da TSP1, cando é illado como un fragmento de 25[[kDa]], é un potente indutor da migración celular a alta concentracións. Porén, cando este dominio é clivado, os restantes dominios anti-anxioxénicos fan diminuír a actividade anti-anxioxénica a baixas concentracións onde ocorre un incremento da migración das [[célula endotelial\|células endoteliais]]. Isto pode ser explicado en parte pola capacidade do dominio de unión á heparina de mediar a unión da TSP1 ás células, permitindo que os outros dominios exerzan os seus efectos. As diferfentes funcións que a rexión de unión á heparina de TSP1 xoga a altas concentracións comparado coa que xoga a baixas concentracións pode ser en parte responsable de regular a dobre natureza do TSP1 e considérase un regulador tanto positivo coma negativo da anxioxénese.<ref name="pmid7686555">{{cite journal \| vauthors = Tolsma SS, Volpert OV, Good DJ, Frazier WA, Polverini PJ, Bouck N \| title = Peptides derived from two separate domains of the matrix protein thrombospondin-1 have anti-angiogenic activity \| journal = The Journal of Cell Biology \| volume = 122 \| issue = 2 \| pages = 497–511 \| date = Jul 1993 \| pmid = 7686555 \| pmc = 2119646 \| doi = 10.1083/jcb.122.2.497 }}</ref> === Dominio de procoláxeno ===▼ ▲=== Dominio de procoláxeno === ▲<!-- Both the procollagen domain and the type I repeats of TSP1 have been shown to inhibit neovascularization and [[endothelial cell\|EC]] migration. However, it is unlikely that the mechanisms of action of these fragments are the same. The type I repeats of TSP1 are capable of inhibiting [[endothelial cell\|EC]] migration in a Boyden chamber assay after a 3-4 hour exposure, whereas a 36- to 48-hour exposure period is necessary for inhibition of [[endothelial cell\|EC]] migration with the procollagen domain.<ref name="pmid7686555"/> Whereas the chorioallantroic membrane (CAM) assay shows the type I repeats of TSP1 to be antiangiogenic, it also shows that the procollagen sequence lacks anti-angiogenic activity. This may be in part because the animo-terminal end of TSP1 differs more than the carboxy-terminal end across species, but may also suggest different mechanisms of action.<ref name="pmid10500044">{{cite journal \| vauthors = Iruela-Arispe ML, Lombardo M, Krutzsch HC, Lawler J, Roberts DD \| title = Inhibition of angiogenesis by thrombospondin-1 is mediated by 2 independent regions within the type 1 repeats \| journal = Circulation \| volume = 100 \| issue = 13 \| pages = 1423–31 \| date = Sep 1999 \| pmid = 10500044 \| doi = 10.1161/01.cir.100.13.1423 \| url = http://circ.ahajournals.org/cgi/content/abstract/100/13/1423 }}</ref>

Trombospondina 1: Diferenzas entre revisións