The Tumor Suppressor Inactivation Antibody Sampler Kit provides a fast and economical means of evaluating the role of COPS5 in the inhibition of the tumor suppressors p27 Kip1, p53, and Smad4. The kit contains enough primary antibody to perform four western blot experiments with each primary antibody.
COPS5 Antibody recognizes endogenous levels of total COPS5 protein. This antibody does not cross-react with PSMD14/POH1. p27 Kip1 (D69C12) XP® Rabbit mAb detects endogenous levels of total p27 Kip1 protein. p53 (7F5) Rabbit mAb detects endogenous levels of total p53 protein. This antibody binding has been mapped to the amino terminal region of human p53 protein. Smad4 Antibody detects endogenous levels of total Smad4 protein.
Monoclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues near the amino terminus of human p27 Kip1 protein or with a full-length human p53 fusion protein. Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues near the amino terminus of human COPS5 protein or to the residues surrounding Pro278 of human Smad4 protein. Polyclonal antibodies are purified by protein A and peptide affinity chromatography.
COPS5/CSN5/Jab1 (c-Jun activation domain-binding protein-1) was originally identified as a transcriptional coactivator of c-Jun and subsequently discovered to be a fifth component and integral part of the CSN (1). As the catalytic center of the CSN, COPS5 is able to integrate multiple functions of the CSN complex such as cell cycle control, transcription, and DNA damage response by regulating the activity of CRLs through deneddylation of cullins (2). Indeed, COPS5 harbors an Mpr1-Pad1-N-terminal (MPN) domain with an embedded Jab1/CSN5 MPN domain metalloenzyme (JAMM) motif that is essential for the CSN isopeptidase activity responsible for deneddylation of CRLs. COPS5 is an evolutionarily conserved 38 kDa protein in humans, mice, fission yeast, and plants, which suggests that it is critical to cell survival and proliferation. A role for COPS5 as a positive regulator of cellular proliferation is supported by evidence that it functionally inactivates several key tumor suppressors such as p53, RUNX3, Smad4, and p27 Kip1 through altered subcellular localization, degradation, and deneddylation (3-7). These findings are underscored by the observation that COPS5 overexpression has been identified in a number of different tumor types and has been implicated in the initiation and progression of several types of cancer (8). Moreover, COPS5 deficient mice display an embryonically lethal phenotype highlighted by elevated expression of COPS5 targets such as p53 and p27 (9,10).
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