Function
ATP8A2 is a catalytic component of a P4-ATPase flippase complex. This complex catalyzes the hydrolysis of ATP, which is coupled to the transport of aminophospholipids from the outer to the inner leaflet of various membranes. This transport ensures the maintenance of asymmetric distribution of phospholipids. Phospholipid translocation is also implicated in vesicle formation and the uptake of lipid signaling molecules. When reconstituted into liposomes, the ATP8A2:TMEM30A flippase complex predominantly transports phosphatidylserine (PS) and, to a lesser extent, phosphatidylethanolamine (PE). Phospholipid translocation is not associated with a countertransport of an inorganic ion or other charged substrate from the cytoplasmic side towards the exoplasm in connection with the phosphorylation from ATP. ATP8A2:TMEM30A may play a role in the regulation of neurite outgrowth. It is proposed to function in the generation and maintenance of phospholipid asymmetry in photoreceptor disc membranes and neuronal axon membranes. It may be involved in vesicle trafficking in neuronal cells. ATP8A2 is essential for normal visual and auditory function; it is involved in the survival of photoreceptor and inner ear spiral ganglion cells.
Gene References Into Functions
- A study describes new ATP8A2 gene mutations associated with a novel syndrome that includes encephalopathy, intellectual disability, severe hypotonia, chorea, and optic atrophy. The data expand both the genetic and phenotypic spectrum associated with ATP8A2 gene mutations. PMID: 27679995
- ATP8A2 is involved in the development of the cerebro-cerebellar structures required for posture and gait. PMID: 22892528
- CDC50A is the beta-subunit of ATP8A2 and is crucial for the correct folding, stable expression, export from the endoplasmic reticulum, and phosphatidylserine flippase activity of ATP8A2. PMID: 21454556
- P4-ATPase Atp8a2 is a phosphatidylserine flippase in photoreceptor disc membranes. PMID: 19778899
Involvement In Disease
Cerebellar ataxia, mental retardation, and dysequilibrium syndrome 4 (CMARQ4)
Protein Families
Cation transport ATPase (P-type) (TC 3.A.3) family, Type IV subfamily
Subcellular Location
Membrane; Multi-pass membrane protein. Golgi apparatus. Endosome. Cell projection, cilium, photoreceptor outer segment. Cell membrane. Photoreceptor inner segment.
Tissue Specificity
Strongly expressed in the brain, cerebellum, retina and testis.