Anti-XAF1 Antibody Picoband® Fluoro550 Conjugated

XAF1 also called XIAP-associated factor 1, antagonizes the anticaspase activity of XIAP and may be important in mediating apoptosis resistance in cancer cells. By genomic sequence analysis, the XAF1 gene contains 7 exons spanning 18 kb. Southern blot analysis suggested that XAF1 is a single-copy gene. The XAF1 gene is mapped on 17p13.1. Fluorescence microscopy demonstrated nuclear expression of XAF1, in contrast to the cytoplasmic expression of XIAP. Functional analysis indicated that XAF1 reverses the XIAP-mediated inhibition of CASP3 and its protection against apoptosis. Northern blot analysis detected wide expression of 3.9-, 4.5-, 6.0-, and 7.0-kb XAF1 transcripts, with highest levels in heart and ovary and lowest levels in brain and testis. Antisense experiments determined that loss of XAF1 expression enhances resistance to apoptosis. Alteration in XAF1 and XIAP RNA expression levels may lead to increased apoptotic resistance and proliferation due to unregulated XIAP function in cancer cells.

Vacuolar protein sorting-associated protein 4B; Cell migration-inducing gene 1 protein; Suppressor of K (+) transport growth defect 1; Protein SKD1; VPS4B; SKD1; VPS42; MIG1

Involved in late steps of the endosomal multivesicular bodies (MVB) pathway. Recognizes membrane-associated ESCRT-III assemblies and catalyzes their disassembly, possibly in combination with membrane fission. Redistributes the ESCRT-III components to the cytoplasm for further rounds of MVB sorting. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. In conjunction with the ESCRT machinery also appears to function in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis and enveloped virus budding (HIV-1 and other lentiviruses) . VPS4A/B are required for the exosomal release of SDCBP, CD63 and syndecan.

1. Bai, Y., Ahmad, U., Wang, Y., Li, J. H., Choy, J. C., Kim, R. W., Kirkiles-Smith, N., Maher, S. E., Karras, J. G., Bennett, C. F., Bothwell, A. L. M., Pober, J. S., Tellides, G. Interferon-gamma induces X-linked inhibitor of apoptosis-associated factor-1 and Noxa expression and potentiates human vascular smooth muscle cell apoptosis by STAT3 activation. J. Biol. Chem. 283: 6832-6842, 2008. 2. 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. 3. 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.