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MT001476

UniProt Annotations

Entry Information

Gene Name	ATPase inhibitory factor 1
Protein Entry	ATIF1_HUMAN
UniProt ID	Q9UII2
Species	Human

Comments

Comment type	Description
Alternative Products	Event=Alternative splicing; Named isoforms=3; Name=1; IsoId=Q9UII2-1; Sequence=Displayed; Name=2; IsoId=Q9UII2-2; Sequence=VSP_041417; Name=3; IsoId=Q9UII2-3; Sequence=VSP_041418;
Domain	Forms an alpha-helical dimer with monomers associated via an antiparallel alpha-helical coiled coil composed of residues 74- 106, leaving each N-terminal inhibitory region (residues 26-52) accessible for interaction with an F1 catalytic domain. The inhibitory N-terminal region (residues 26-52) binds the alpha(ADP- bound)-beta(ADP-bound) (ATP5A1-ATP5B) interface of F1-ATPase, and also contact the central gamma subunit (ATP5C1). This dimeric state is favored by pH values below 7.0, and at higher values the dimers associate to form inactive homotetramer, where the inhibitory region is occluded, masking its inhibitory activity (By similarity). {ECO:0000250}.
Function	Endogenous F(1)F(o)-ATPase inhibitor limiting ATP depletion when the mitochondrial membrane potential falls below a threshold and the F(1)F(o)-ATP synthase starts hydrolyzing ATP to pump protons out of the mitochondrial matrix. Required to avoid the consumption of cellular ATP when the F(1)F(o)-ATP synthase enzyme acts as an ATP hydrolase. Indirectly acts as a regulator of heme synthesis in erythroid tissues: regulates heme synthesis by modulating the mitochondrial pH and redox potential, allowing FECH to efficiently catalyze the incorporation of iron into protoporphyrin IX to produce heme. {ECO:0000269\|PubMed:12110673, ECO:0000269\|PubMed:15528193, ECO:0000269\|PubMed:19559621, ECO:0000269\|PubMed:23135403}.
Ptm	Exhibits variability in chain length, mitochondria have distinct pools of protein cleaved after the 24th, 25th, and 26th amino acid.
Sequence Caution	Sequence=AAH04955.1; Type=Erroneous initiation; Note=Translation N-terminally extended.; Evidence={ECO:0000305};
Similarity	Belongs to the ATPase inhibitor family. {ECO:0000305}.
Subcellular Location	Mitochondrion {ECO:0000269\|PubMed:12110673}.
Subunit	Homodimer; represents the active form and is present at a pH value below 6.5. Homotetramer; represents the inactive form and is present at a pH value above 7.0 (By similarity). {ECO:0000250}.