The function of Ensembl gene identifier ENSG00000054793 (ATP9A, ATPase phospholipid transporting 9A) is as follows. Plays a role in regulating membrane trafficking of cargo proteins, namely endosome to plasma membrane recycling, probably acting through RAB5 and RAB11 activation (PubMed:27733620, PubMed:30213940, PubMed:36604604). Also involved in endosome to trans-Golgi network retrograde transport (PubMed:27733620, PubMed:30213940). In complex with MON2 and DOP1B, regulates SNX3 retromer-mediated endosomal sorting of WLS, a transporter of Wnt morphogens in developing tissues. Participates in the formation of endosomal carriers that direct WLS trafficking back to Golgi, away from lysosomal degradation (PubMed:30213940). Appears to be implicated in intercellular communication by negatively regulating the release of exosomes (PubMed:30947313). The flippase activity towards membrane lipids and its role in membrane asymmetry remains to be proved (PubMed:30947313). Required for the maintenance of neurite morphology and synaptic transmission (By similarity). {ECO:0000250|UniProtKB:O70228, ECO:0000269|PubMed:27733620, ECO:0000269|PubMed:30213940, ECO:0000269|PubMed:30947313, ECO:0000269|PubMed:36604604}.