6k7i
From Proteopedia
Cryo-EM structure of the human P4-type flippase ATP8A1-CDC50 (E1-ATP state class2)
Structural highlights
FunctionAT8A1_HUMAN Catalytic component of a P4-ATPase flippase complex which catalyzes the hydrolysis of ATP coupled to the transport of aminophospholipids from the outer to the inner leaflet of various membranes and ensures the maintenance of asymmetric distribution of phospholipids (PubMed:31416931). Phospholipid translocation seems also to be implicated in vesicle formation and in uptake of lipid signaling molecules. In vitro, its ATPase activity is selectively and stereospecifically stimulated by phosphatidylserine (PS) (PubMed:31416931). The flippase complex ATP8A1:TMEM30A seems to play a role in regulation of cell migration probably involving flippase-mediated translocation of phosphatidylethanolamine (PE) at the cell membrane (By similarity). Acts as aminophospholipid translocase at the cell membrane in neuronal cells (By similarity).[UniProtKB:P70704][1] Publication Abstract from PubMedIn eukaryotic membranes, P4-ATPases mediate the translocation of phospholipids from the outer to inner leaflet and maintain lipid asymmetry, which is critical for membrane trafficking and signaling pathways. Here we report the cryo-EM structures of six distinct intermediates of the human ATP8A1-CDC50a hetero-complex, at 2.6-3.3 A resolutions, elucidating lipid translocation cycle of this P4-ATPase. ATP-dependent phosphorylation induces a large rotational movement of the actuator domain around the phosphorylation site in the phosphorylation domain, accompanied by lateral shifts of the first and second transmembrane helices, thereby allowing phosphatidylserine binding. The phospholipid head group passes through the hydrophilic cleft, while the acyl chain is exposed toward the lipid environment. These findings advance our understanding of the flippase mechanism and the disease-associated mutants of P4-ATPases. Cryo-EM structures capture the transport cycle of the P4-ATPase flippase.,Hiraizumi M, Yamashita K, Nishizawa T, Nureki O Science. 2019 Aug 15. pii: science.aay3353. doi: 10.1126/science.aay3353. PMID:31416931[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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