Disease relevance of Rpa1

• The Rpa1 mutation resulted in defects in DNA double-strand break repair and precipitated chromosomal breaks as well as aneuploidy in primary heterozygous mutant mouse embryonic fibroblasts [1].
• Finally, we have shown that T-cell nuclear proteins which bind the E3 motif bear p70 (Ku) lupus autoantigenic determinants [2].
• Previous studies identified two glycoproteins of 86 (gp86) and 72 (gp72) kilodaltons and two nonglycosylated proteins of 70 (p70) and 19 (p19) kilodaltons which were specifically expressed in NIH cells transformed by DNA of the MCF-7 human mammary carcinoma cell line [3].
• Moreover, HHV-6, but not the closely related betaherpesvirus HHV-7, dramatically suppressed the secretion of interleukin-12 (IL-12) p70 by DC, while the production of other cytokines that influence DC maturation, i.e., IL-10 and tumor necrosis factor alpha, was not significantly modified [4].
• The inhibitory effect of indomethacin on papilloma formation was again reversed by PGF2 alpha treatment concomitant with RPA [5].

High impact information on Rpa1

• Mutation in Rpa1 results in defective DNA double-strand break repair, chromosomal instability and cancer in mice [1].
• In somatic cells, DNA damage induces ATM-dependent phosphorylation of RPA [6].
• ATM and RPA in meiotic chromosome synapsis and recombination [6].
• A potential target of cyclin A and cdk2 is the 34 kd subunit of replication protein A (RPA34) [7].
• The data presented are most consistent with the existence of a 70- to 77-kilodalton glycoprotein subunit (p70) which, upon associating with the 55-kilodalton low-affinity receptor (p55), transforms it into a high-affinity site [8].

Chemical compound and disease context of Rpa1

• Functionally, PGE2 was previously shown to be an endogenous mediator of the TPA- or RPA-induced epidermal hyperproliferation and hyperplasia [5].
• The torsion angle C5'-C6'-C7'-C8', determining the conformation of the RBP-beta-ionone-ring relative to the isoprene tail, is rotated by 42 degrees for RPA compared to retinol and to retinoic acid, respectively [9].

Biological context of Rpa1

• These molecules included not only those involved in cell cycle progression, but also essential molecules for DNA double-strand break repair, such as Rad51 and Rpa1 [10].
• To gain insight into the role of BRCA2 in the repair of DNA damage, we fused a single (BRC3, BRC4) or multiple BRC motifs to the large RPA subunit [11].
• MAbs N3H10 and S5C11 bound immediately adjacent to the DNA binding site of p70 (amino acids 506-541) [12].
• The intranuclear location of the IL-2R suggests that the p55 subunit, either alone or in conjunction with the IL-2 or the p70 subunit, may be implicated in the regulation of gene expression involved in T cell proliferation [13].
• The p70 gene, named Helios, encodes two protein isoforms with zinc finger domains exhibiting considerable homology to those within Ikaros proteins [14].

Anatomical context of Rpa1

• In an effort to identify cellular helicases that mimic the action of SV40 large T-antigen, we performed replication protein A (RPA) affinity chromatography on cell extracts from the mouse mammary carcinoma cell line FM3A [15].
• In Atm-/- meiotic prophase spermatocytes, immuno-localization shows that RPA is present along synapsing chromosomes and at sites of fragmentation of the SC [6].
• CD40 triggering of heterodimeric IL-12 p70 production by dendritic cells in vivo requires a microbial priming signal [16].
• The murine c-fgr gene product associated with Ly6C and p70 integral membrane protein is expressed in cells of a monocyte/macrophage lineage [17].
• We now provide evidence that hydrogen peroxide (H2O2), a major component of ROSs, inhibits interleukin-12 (IL-12) p40 and IL-12 p70 induction in murine macrophages and catalase pretreatment prevents H2O2-mediated down-regulation of IL-12 [18].

Associations of Rpa1 with chemical compounds

• Tryptophan fluorescence studies indicated significant quenching of Trp-361, located in the DBD-B domain, induced by hyperphosphorylation of RPA [19].
• The IL-2 receptor beta-chain (p70). Ligand binding ability of the cDNA-encoding membrane and secreted forms [20].
• Finally, we show that anisomycin augments and prolongs S6 phosphorylation not by blocking S6 phosphatases but by sustained activation of p70/85S6k [21].
• We purified p70 with a a one-step RNA affinity purification procedure with the biotin-labeled 5'-UTR [22].
• A functional role of PGF2 alpha could be attributed to the post-initiation stages of tumor development in initiated mouse skin, i.e. the conversion stage (stage I of tumor promotion) elicited by two TPA applications and the promotion stage (stage II of promotion) brought about repetitive RPA treatments [5].

Co-localisations of Rpa1

• Here we show that Cdk4 colocalizes with replication protein A (RPA) on the synaptonemal complexes (SCs) of newly synapsed axes of homologously pairing bivalents, but disappears from these axes by mid-pachynema [23].

Other interactions of Rpa1

• Molecular readouts of the properties of IR repair have been identified, including the hyperphosphorylation of the 34 kDa subunit of replication protein A. In addition, we have identified features of the G1/S IR-induced checkpoint that can be influenced by p53 status, genetic background or the levels of cell cycle proteins [24].
• In biochemical assays, replication protein A (RPA), a ssDNA-binding protein, associates with phosphorylated AID from activated B cells and enhances AID activity on transcribed double-stranded (ds)DNA containing somatic hypermutation or CSR target sequences [25].

Analytical, diagnostic and therapeutic context of Rpa1

• A DNA helicase purified by replication protein A (RPA) affinity chromatography from mouse FM3A cells [15].
• To understand how the hyperphosphorylation modulates the functions of RPA, we compared the structural characteristics of full-length native and hyperphosphorylated RPAs using mass spectrometric protein footprinting, fluorescence spectroscopy, and limited proteolysis [19].
• These studies substantiate the role of the p70 receptor chain in functional responses to IL-2 and provide a model system for future dissection of the structure/function relationships of the IL-2 receptor [26].
• Nevertheless, after DC activation by microbial stimuli that primarily upregulate IL-12 p40 and augment CD40 expression, CD40 ligation induces a significant increase in IL-12 p35 and IL-12 p70 heterodimer production [16].
• Quantitative PCR and in situ hybridization for IL-12 p40 and an ELISA specific for the p70 heterodimer were used to determine IL-12 production [27].

References