A unique gating mechanism revealed by the cryo-EM structure of monomeric ATP9A flippase.

ABSTRACT: Among mammalian P4-ATPase flippases, only ATP9A and ATP9B do not require the auxiliary subunit CDC50 protein. Whilst its yeast homolog, Neo1, is essential for cell survival, little is known about mammalian ATP9A. We present cryo-EM structures of human monomeric ATP9A at a resolution reaching 2.2 Å, in the outward-facing E2P state. Two distinguishable conformations were obtained from a single sample, one with its outward gate open and the other in its closed form. Unlike canonical gating observed for most P-type ATPases, which is driven by the movement of transmembrane (TM) helices 1 and 2 linked to the A domain, outward gating in ATP9A is achieved by the movement of TM6-10 helices, likely initiated by the unwinding of TM6. As a result, the volume of the phospholipid binding cavity in the o

SUBMITTER: Abe K 

PROVIDER: S-EPMC12494553 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature