PSMD14 Antibody

7662:

Western Blotting

PSMD14 Antibody recognizes endogenous levels of total PSMD14 protein. This antibody does not cross-react with COPS5.

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Gly182 of human PSMD14 protein. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western blot analysis of extracts from various cell lines using PSMD14 Antibody.

Western Blotting

Western blot analysis of extracts from 293T cells, either mock transfected (-) or transfected with Myc/DDK-tagged cDNA expression constructs encoding full-length human COPS5 (hCOPS5, +) or full-length human PSMD14 (hPSMD14, +), using PSMD14 Antibody (upper) and DYKDDDDK Tag Antibody (Binds to same epitope as Sigma's Anti-FLAG^® M2 Antibody) #2368 (lower).

The 26S proteasome is a highly abundant ~2 MDa complex that serves as the proteolytic arm of the ubiquitin-proteasome system. It consists largely of two sub-complexes, the 19S regulatory particle (RP) and the 20S catalytic core particle (CP), and in many cases two RPs cap either end of a CP. The CP is made of two stacked β-rings that contain the catalytic sites, each of which is made of seven subunits (β_1-7 ), flanked on either side by two α-rings, which are also made of seven subunits each. Thus, the structure of the 20S CP is α_1-7 β_1-7 β_1-7 α_1-7 . The RP includes a base and a lid. The base, in part, is composed of a hexametric ring of ATPases that function to unfold the substrate and open the gate of the interlacing N-terminal segments of the α-subunits, thus allowing entry of the unfolded substrate into the catalytic chamber. The lid is predominantly involved in specific recognition of the ubiquitin signal (1). In addition to the 19S cap, other proteins and complexes, such as proteasome activator 28 (PA28/11S), bind to the end of the 20S cylinder and activate it by facilitating opening of the gate. Furthermore, proteasome-associated DUBs and E3s can remodel substrate-anchored polyubiquitin chains, which may modulate their susceptibility to degradation (2).

Of the subunits that comprise the 19S RP lid, only PSMD14 (POH1) has a known function. PSMD14 is classified as a metalloenzyme DUB and its activity has been shown to be critical for proteasome function in both yeast and humans (3-6). Indeed, PSMD14 harbors an Mpr1-Pad1-N-terminal (MPN) domain with an embedded, highly conserved signature motif for metal-dependent isopeptidases that has been dubbed JAMM, from Jab1/Pad1/MPN domain metalloenzyme. The JAMM motif of PSMD14 consists of a pattern of four charged amino acids: a glutamate residue followed by two histidines and an aspartate (EX_n HXHX₁₀ D). It has been proposed that the histidine residues, in concert with the aspartate, bind to a zinc ion that, together with the preceding glutamate, forms the catalytic site of PSMD14 (3,4). PSMD14 is thought to cleave ubiquitin chains with proximal specificity relative to the substrate, thus removing whole ubiquitin chains en bloc (3). Recent studies have implicated PSMD14 as an important regulator of ErbB2 (7) and c-Jun (8) protein levels.

1. Finley, D. (2009) Annu Rev Biochem 78, 477-513.
2. Lee, M.J. et al. (2011) Mol Cell Proteomics 10, R110.003871.
3. Verma, R. et al. (2002) Science 298, 611-5.
4. Yao, T. and Cohen, R.E. (2002) Nature 419, 403-7.
5. Maytal-Kivity, V. et al. (2002) BMC Biochem 3, 28.
6. Gallery, M. et al. (2007) Mol Cancer Ther 6, 262-8.
7. Liu, H. et al. (2009) PLoS One 4, e5544.
8. Nabhan, J.F. and Ribeiro, P. (2006) J Biol Chem 281, 16099-107.

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• 7003 20X LumiGLO^® Reagent and 20X Peroxide
• 9998 BSA
• 9999 Nonfat Dry Milk

For Research Use Only. Not For Use In Diagnostic Procedures.