AIFM1

This gene encodes a flavoprotein essential for nuclear disassembly in apoptotic cells, and it is found in the mitochondrial intermembrane space in healthy cells. Induction of apoptosis results in the translocation of this protein to the nucleus where it affects chromosome condensation and fragmentation. In addition, this gene product induces mitochondria to release the apoptogenic proteins cytochrome c and caspase-9. Mutations in this gene cause combined oxidative phosphorylation deficiency 6 (COXPD6), a severe mitochondrial encephalomyopathy, as well as Cowchock syndrome, also known as X-linked recessive Charcot-Marie-Tooth disease-4 (CMTX-4), a disorder resulting in neuropathy, and axonal and motor-sensory defects with deafness and cognitive disability. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 10. [provided by RefSeq, Aug 2015]

Apoptosis Inducing Factor Mitochondria Associated 1

Functions both as NADH oxidoreductase and as regulator of apoptosis (PubMed:20362274, PubMed:23217327, PubMed:17094969). In response to apoptotic stimuli, it is released from the mitochondrion intermembrane space into the cytosol and to the nucleus, where it functions as a proapoptotic factor in a caspase-independent pathway. The soluble form (AIFsol) found in the nucleus induces 'parthanatos' i.e. caspase-independent fragmentation of chromosomal DNA (By similarity). Binds to DNA in a sequence-independent manner (PubMed:27178839). Interacts with EIF3G, and thereby inhibits the EIF3 machinery and protein synthesis, and activates caspase-7 to amplify apoptosis (PubMed:17094969). Plays a critical role in caspase-independent, pyknotic cell death in hydrogen peroxide-exposed cells (PubMed:19418225). In contrast, participates in normal mitochondrial metabolism. Plays an important role in the regulation of respiratory chain biogenesis by interacting with CHCHD4 and controlling CHCHD4 mitochondrial import (PubMed:26004228).
Isoform 4: Has NADH oxidoreductase activity. Does not induce nuclear apoptosis.
Isoform 5: Pro-apoptotic isoform.

Activation of cysteine-type endopeptidase activity involved in apoptotic process Source: UniProtKB
Apoptotic process Source: UniProtKB
Chromosome condensation Source: UniProtKB
Intrinsic apoptotic signaling pathway in response to endoplasmic reticulum stress Source: UniProtKB
Mitochondrial respiratory chain complex assembly Source: UniProtKB
Mitochondrial respiratory chain complex I assembly Source: UniProtKB
Neuron differentiation Source: UniProtKB
Positive regulation of apoptotic process Source: UniProtKB
Protein import into mitochondrial intermembrane space Source: UniProtKB

Nucleus; Cytoplasm; Mitochondrion intermembrane space; Mitochondrion inner membrane; Perinuclear region. Proteolytic cleavage during or just after translocation into the mitochondrial intermembrane space (IMS) results in the formation of an inner-membrane-anchored mature form (AIFmit). During apoptosis, further proteolytic processing leads to a mature form, which is confined to the mitochondrial IMS in a soluble form (AIFsol). AIFsol is released to the cytoplasm in response to specific death signals, and translocated to the nucleus, where it induces nuclear apoptosis (PubMed:15775970). Colocalizes with EIF3G in the nucleus and perinuclear region (PubMed:17094969).
Isoform 3: Mitochondrion intermembrane space; Mitochondrion inner membrane. Has a stronger membrane anchorage than isoform 1.
Isoform 4: Cytosol; Mitochondrion. In pro-apoptotic conditions, is released from mitochondria to cytosol in a calpain/cathepsin-dependent manner.
Isoform 5: Cytoplasm

Combined oxidative phosphorylation deficiency 6 (COXPD6): A mitochondrial disease resulting in a neurodegenerative disorder characterized by psychomotor delay, hypotonia, areflexia, muscle weakness and wasting. Some patients manifest prenatal ventriculomegaly and severe postnatal encephalomyopathy.
Charcot-Marie-Tooth disease, X-linked recessive, 4, with or without cerebellar ataxia (CMTX4): A neuromuscular disorder characterized by progressive sensorimotor axonal neuropathy, distal sensory impairment, difficulty walking due to peripheral neuropathy and/or cerebellar ataxia, and deafness due to auditory neuropathy. Additional features include cognitive impairment, cerebellar atrophy, dysarthria, abnormal extraocular movements, tremor, dysmetria and spasticity. The age at onset ranges from infancy to young adulthood.
Deafness, X-linked, 5, with peripheral neuropathy (DFNX5): A form of hearing loss characterized by absent or severely abnormal auditory brainstem response, abnormal middle ear reflexes, abnormal speech discrimination, loss of outer hair cell function, and cochlear nerve hypoplasia. DFNX5 patients manifest auditory neuropathy with childhood onset, associated with distal sensory impairment affecting the peripheral nervous system.
Spondyloepimetaphyseal dysplasia, X-linked, with hypomyelinating leukodystrophy (SEMDHL): An X-linked recessive developmental disorder characterized by slowly progressive skeletal and neurologic abnormalities, including short stature, large and deformed joints, significant motor impairment, visual defects, and sometimes cognitive deficits. Affected individuals typically have normal early development in the first year or so of life, followed by development regression and the development of symptoms. Brain imaging shows white matter abnormalities consistent with hypomyelinating leukodystrophy.

Under normal conditions, a 54-residue N-terminal segment is first proteolytically removed during or just after translocation into the mitochondrial intermembrane space (IMS) by the mitochondrial processing peptidase (MPP) to form the inner-membrane-anchored mature form (AIFmit). During apoptosis, it is further proteolytically processed at amino-acid position 101 leading to the generation of the mature form, which is confined to the mitochondrial IMS in a soluble form (AIFsol). AIFsol is released to the cytoplasm in response to specific death signals, and translocated to the nucleus, where it induces nuclear apoptosis in a caspase-independent manner.
Ubiquitination by XIAP/BIRC4 does not lead to proteasomal degradation. Ubiquitination at Lys-255 by XIAP/BIRC4 blocks its ability to bind DNA and induce chromatin degradation, thereby inhibiting its ability to induce cell death.