Anti-Cullin 4B/CUL4B Antibody Picoband® Fluoro647 Conjugated

Cullin 4B/CUL4B encodes a scaffold protein that organizes a cullin-RING (really interesting new gene) ubiquitin ligase (E3) complex in ubiquitylation. The CUL4 gene encodes a protein of 913 amino acids. The cullin domain is located between amino acid residues 217 and 815 and is characterized a by C-terminal globular domain (cullin homology domain) and a series of N-terminal repeats (cullin repeats) . Ohtake et al. (2007) characterize a fat-soluble ligand-dependent ubiquitin ligase complex in human cell lines, in which dioxin receptor (AhR) is integrated as a component of a novel cullin 4B ubiquitin ligase complex, CUL4B (AhR) . Complex assembly and ubiquitin ligase activity of CUL4B (AhR) in vitro and in vivo are dependent on the AhR ligand. In the CUL4B (AhR) complex, ligand-activated AhR acts as a substrate-specific adaptor component that targets sex steroid receptors for degradation. Their findings uncover a function for AhR as an atypical component of the ubiquitin ligase complex and demonstrate a non-genomic signalling pathway in which fat-soluble ligands regulate target-protein-selective degradation through a ubiquitin ligase complex.

Bcl-X (S) is expressed at high levels in cells that undergo a high rate of turnover, such as developing lymphocytes. In contrast, Bcl-X (L) is found in tissues containing long-lived postmitotic cells, such as adult brain.

Apoptosis, Apoptotic Markers, Cancer, Cell Biology, Cell Death, Intracellular, Invasion/Microenvironment, Metabolism, Metabolism Processes, Pathways and Processes

Core component of multiple cullin-RING-based E3 ubiquitin-protein ligase complexes which mediate the ubiquitination and subsequent proteasomal degradation of target proteins. The functional specificity of the E3 ubiquitin-protein ligase complex depends on the variable substrate recognition subunit. CUL4B may act within the complex as a scaffold protein, contributing to catalysis through positioning of the substrate and the ubiquitin-conjugating enzyme. Plays a role as part of the E3 ubiquitin-protein ligase complex in polyubiquitination of CDT1, histone H2A, histone H3 and histone H4 in response to radiation- induced DNA damage. Targeted to UV damaged chromatin by DDB2 and may be important for DNA repair and DNA replication. Required for ubiquitination of cyclin E, and consequently, normal G1 cell cycle progression. Regulates the mammalian target-of-rapamycin (mTOR) pathway involved in control of cell growth, size and metabolism. Specific CUL4B regulation of the mTORC1-mediated pathway is dependent upon 26S proteasome function and requires interaction between CUL4B and MLST8. .

1. Zou, Y.; Liu, Q.; Chen, B.; Zhang, X.; Guo, C.; Zhou, H.; Li, J.; Gao, G.; Guo, Y.; Yan, C.; Wei, J.; Shao, C.; Gong, Y. : Mutation in CUL4B, which encodes a member of cullin-RING ubiquitin ligase complex, causes X-linked mental retardation. Am. J. Hum. Genet. 80: 561-566, 2007. 2. Tarpey, P. S.; Raymond, F. L.; O'Meara, S.; Edkins, S.; Teague, J.; Butler, A.; Dicks, E.; Stevens, C.; Tofts, C.; Avis, T.; Barthorpe, S.; Buck, G. : {and 41 others}: Mutations in CUL4B, which encodes a ubiquitin E3 ligase subunit, cause an X-linked mental retardation syndrome associated with aggressive outbursts, seizures, relative macrocephaly, central obesity, hypogonadism, pes cavus, and tremor. Am. J. Hum. Genet. 80: 345-352, 2007. 3. Ohtake, F.; Baba, A.; Takada, I.; Okada, M.; Iwasaki, K.; Miki, H.; Takahashi, S.; Kouzmenko, A.; Nohara, K.; Chiba, T.; Fujii-Kuriyama, Y.; Kato, S. : Dioxin receptor is a ligand-dependent E3 ubiquitin ligase. Nature 446: 562-566, 2007.