Seminario Biologia Celular

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  • Existem trs classes de bombas acionadas por ATPBombas do tipo P

    Bombas do tipo F

    Transportadores ABC

  • A bomba de Ca+2 a ATPase do tipo P melhor compreendidaPresente na membrana do retculo sarcoplasmtico das clulas (presente em menor nmero em clulas no musculares) A fosforilao do cido asprtico leva a um rearranjo das hlices transmembrana, que desestrutura o stio de ligao do Ca2+ e libera os ons de Ca2+

  • Clulas que superexpressam Ca2+ ATPases contm um stio de ligao altamente conservado onde o fofatidilinositol se liga, e regula as bombas.

  • A bomba Na+ / K+ da membrana plasmtica estabelece o gradiente de Na+ atravs da membrana plasmtica

  • A bomba Na+ / K+ da membrana plasmtica estabelece o gradiente de Na+ atravs da membrana plasmtica

  • Os transportadores ABC constituem a maior famlia de protenas de transporte de membrana

  • Os transportadores ABC constituem a maior famlia de protenas de transporte de membrana

  • Os transportadores ABC constituem a maior famlia de protenas de transporte de membrana

    We show that in PMCAoverexpressing cells, PtdIns(4,5)P2 binding can lead to less inositol1,4,5-triphosphate (InsP3) and diminished Ca2+ release fromintracellular Ca2+ pools. Inspection of a homology model of PMCAsuggests that PMCAs have a conserved cluster of basic residuesforming a blue collar at the interface between the membrane coreand the cytoplasmic domains. By molecular dynamics simulation,we found that the blue collar forms four binding pockets for thephosphorylated inositol head group of PtdIns(4,5)P2; these pocketsbind PtdIns(4,5)P2 strongly and frequently. Our studies suggest thatby having the ability to bind PtdIns(4,5)P2, PMCAs can control theaccessibility of PtdIns(4,5)P2 for PLC and other PtdIns(4,5)P2-mediated processes.