Anti-XIAP-associated factor 1 XAF1 Antibody Picoband® Fluoro647 Conjugated

XIAP associated factor-1, also known as XAF1, is a human gene. X-linked inhibitor of apoptosis (XIAP; MIM 300079) is a potent member of the IAP family. All members of this family possess baculoviral IAP (BIR) repeats, cysteine-rich domains of approximately 80 amino acids that bind and inhibit caspases. XAF1 antagonizes the anticaspase activity of XIAP and may be important in mediating apoptosis resistance in cancer cells. And alteration in XAF1 and XIAP RNA expression levels may lead to increased apoptotic resistance and proliferation due to unregulated XIAP function in cancer cells.

Widely expressed. Expression is frequently down-regulated in cancer cell lines. Isoform 5 is widely expressed. Expressed in placenta (at protein level) . .

Seems to function as a negative regulator of members of the IAP (inhibitor of apoptosis protein) family. Inhibits anti- caspase activity of BIRC4. Induces cleavage and inactivation of BIRC4 independent of caspase activation. Mediates TNF-alpha- induced apoptosis and is involved in apoptosis in trophoblast cells. May inhibit BIRC4 inly by activating the mitochondrial apoptosis pathway. After translocation to mitochondra, promotes translocation of BAX to mitochondria and cytochrome c release from mitochondria. Seems to promote the redistribution of BIRC4 from the cytoplasm to the nucleus, probably independent of BIRC4 inactivation which seems to occur in the cytoplasm. The BIRC4-XAF1 complex mediates down-regulation of BIRC5/survivin; the process requires the E3 ligase activity of BIRC4. Seems to be involved in cellular sensitivity to the proapoptotic actions of TRAIL. May be a tumor suppressor by mediating apoptosis resistance of cancer cells. .

1. Fong, W. G.; Liston, P.; Rajcan-Separovic, E.; St. Jean, M.; Craig, C.; Korneluk, R. G. : Expression and genetic analysis of XIAP-associated factor 1 (XAF1) in cancer cell lines. Genomics 70: 113-122, 2000. 2. Liston, P.; Fong, W. G.; Kelly, N. L.; Toji, S.; Miyazaki, T.; Conte, D.; Tamai, K.; Craig, C. G.; McBurney, M. W.; Korneluk, R. G. : Identification of XAF1 as an antagonist of XIAP anti-caspase activity. Nature Cell Biol. 3: 128-133, 2001.

Cytoplasm. Nucleus. Mitochondrion. Found in the cytoplasm and nucleus of placental syncytiotrophoblasts. Translocates to mitochondria upon TNF-alpha treatment.