Disease relevance of PSMC1

• Comparison of the proteins of DpCPV with those of other members in the family Reoviridae lead us to suggest that S1, S3, S4 and S6 encode the viral structural protein VP1, VP2, VP3 and VP4, respectively [1].
• These mature cellular antiviral mRNAs are not produced after infection with influenza A virus, but IFN regulatory factor-3 is activated and the transcription of the ISRE-controlled p56 gene is induced [2].
• Antibodies reactive with human T-cell leukemia virus type I (HTLV-I) proteins p19, p24, gp46, p56, and gp68 were detected in four of 27 patients with mycosis fungoides/Sézary syndrome (MF/SS) and one patient with Kaposi's sarcoma using radioimmunoprecipitation and Western blot analysis [3].
• In this paper, the effect of heat stress on the rate of synthesis of p56 is determined [4].
• We screened a human placenta cDNA library by yeast two-hybrid assay using HPV 16 E7 as a bait and identified the subunit 4 (S4) ATPase of the 26 S proteasome as a novel E7-binding protein [5].

High impact information on PSMC1

• In addition, we provide genetic evidence for a physical interaction between the S4 and the related S7 subunit in the 26S multiprotein protease [6].
• Comparison of tryptic peptide maps of the bcl-3 protein synthesized in vitro, and p56 and p38 from HeLa cells, shows that they are all structurally related [7].
• Specifically, in vitro and in vivo co-precipitation studies have revealed that the 19S regulatory components of the proteasome, Sug1 (S8) and S4, bind through amino acids (aa) 4-25 of Ad5 E1A [8].
• In mature sperm, p56 is located at the tip and base of the nucleus from where it is removed by egg cytosol in vitro [9].
• In the egg, p56 is present in a subset of cytoplasmic membranes (MV2 beta) which contributes the bulk of the nuclear envelope during male pronuclear formation. p56-containing vesicles are required for nuclear envelope assembly and have a chromatin-binding capacity that is mediated by p56 [9].

Chemical compound and disease context of PSMC1

• The increased hydrophobicity due to the Pro12 insertion and the presence of more aromatic residues in the S4 subsite of Mo-MuLV PR compared to HIV-1 and HIV-2 PRs can be correlated with the observed differences using P4-substituted analogs of VSQNYPIVQ [10].
• 1-beta-D-arabinofuranosylcytosine activates tyrosine phosphorylation of p34cdc2 and its association with the Src-like p56/p53lyn kinase in human myeloid leukemia cells [11].

Biological context of PSMC1

• The phosphorylation of S4 was confirmed by double immunoprecipitation experiments in which 26S proteasomes were immunoprecipitated as above and dissociated and then S4 was immunoprecipitated with subunit-specific antibodies [12].
• Antiserum to recombinant yeast subunit mts2 (mitosis temperature sensitive gene 2; S4) did not react with any protein of the expected size but detected a 30-kDa peptide that was not associated with the 26S proteasome; this was found only in muscle from the layer strain [13].
• For this study we determined the nucleotide sequences of the T2W S1, S2, S3 and S4 genome segments to allow molecular comparison with other reoviruses [14].
• The data suggest that p56 is a translational product of the c-ets proto-oncogene and imply that p56 may be involved in regulating the growth of lymphoid cells [15].
• APC was chemically modified to create the FRET donor species, Fl-FPR-APC, with a fluorescein dye (Fl) covalently attached to the active site via a D-Phe-Pro-Arg (FPR) tether and located in the active site near S4 [16].

Anatomical context of PSMC1

• Immunochemical accessibility of ribosomal protein S4 in the 30 S ribosome. The interaction of S4 with S5 and S12 [17].
• We suggest that p56 is a sea urchin LBR homologue that targets membranes to chromatin and later anchors the membrane to the lamina [9].
• Several housekeeping genes including U6 small nuclear RNA (snRNA), ribosomal proteins S4 and S13, a core protein of the spliceosome [small nuclear ribonucleoprotein (snRNP) E], and a cip-like protease (clpP) were identified [18].
• The absorbed anti-bp90 serum retained the ability to immunoprecipitate P135gag-mybE-ets from E26-transformed cells and specifically reacted with a 56-kilodalton polypeptide (p56) detected in chicken lymphoid organs and in T and B lymphocytes of both avian and human origin [15].
• CD2-mediated interleukin-2 production occurs via activation of Jun kinase in cell lines lacking p56 [19].

Associations of PSMC1 with chemical compounds

• Since S4-like ATPases contain putative coiled-coils within the first 150 NH2-terminal amino acids, we propose that coiled-coil interactions are responsible for the specificity of the observed subunit associations and that these associations are important for self-assembly of the regulatory complex [20].
• Compared with other trypsin-like serine proteases, the S2 and S3/S4 pockets of uPA are reduced in size because of the 99-insertion loop [21].
• Nuclear signaling induced by ionizing radiation involves colocalization of the activated p56/p53lyn tyrosine kinase with p34cdc2 [22].
• It is proposed that p56 is a steroid receptor-associated heat shock protein which can now be termed hsp56 [4].
• Induction of p56 also occurs in IM-9 cells subjected to chemical stress (sodium arsenite) [4].

Physical interactions of PSMC1

• Progressive COOH-terminal deletions that removed as much as 300 amino acids from S4 had no effect on the binding of S4 to S7 [20].

Other interactions of PSMC1

• These results suggest a role for S4 and ubiquitin-mediated proteasomal proteolysis in the molecular pathogenesis of SCA7 [23].
• In striking contrast, truncation of 85 NH2-terminal amino acids from S4 abrogated binding, clearly implicating the NH2 terminus of S4 in its specific interaction with S7 [20].
• Here we demonstrate that PSMC1, an ATPase-like subunit of the 19 S proteasome component, also interacts with HBX and PSMA7 [24].
• S4, S6, S10b, and S6' displayed specific binding to components of the regulatory complex separated by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) or two-dimensional PAGE [20].
• The effect of S5 and S12 on S4 accessibility is consistent with data from a variety of other approaches, suggesting that these proteins form a structural and functional domain in the small ribosomal subunit [17].

Analytical, diagnostic and therapeutic context of PSMC1

• Analysis of the interacting domains among PSMA7, PSMC1, and HBX by deletion and site-directed mutagenesis suggested a mutually competitive structural relationship among these polypeptides [24].
• We also examined distribution of RNA polymerase II and 26S proteasome subunit 4 (S4) within the mouse brain by in situ hybridization [25].
• Immunofluorescence studies revealed that hPNGase, hHR23B, and hS4 are present in close proximity to the endoplasmic reticulum (ER) when calnexin was used as an ER marker in HeLa cells [26].
• Ligation of the T cell antigen receptor (TCR) activates the Src family tyrosine kinase p56 Lck, which, in turn, phosphorylates a variety of intracellular substrates [27].
• By using in vivo chemical cross-linking and affinity chromatography techniques, we found that UDG is a cellular target for the early viral protein p56 [28].

References