Disease relevance of RGS1

• RGS1 and RGS13 mRNA silencing in a human B lymphoma line enhances responsiveness to chemoattractants and impairs desensitization [1].
• Two of these proteins, RGS1 and RGS13, are well-expressed in germinal center B cells and many Burkitt's lymphoma cell lines [1].
• The products of RGS1, RGS2, ANX2 and CD44H were suggested to promote tumour metastasis [2].
• In addition, high levels of BL34 mRNA were detected in RNA purified from PBMC of a patient with B cell acute lymphocytic leukemia [3].
• G0S8 has been mapped using fluorescence in situ hybridization (FISH) to human chromosome 1q31, the same site reported for the B cell homolog BL34/1R20 and within a region implicated in the development of hematological malignancies [4].
• Our findings indicate that uSpA PBMCs carry strikingly more highly expressed genes compared with PBMCs from AS patients or healthy subjects, and that TNFalpha- and IL-17-inducible RGS1 is a potential biomarker for uSpA, and to a lesser extent for AS, with inflammatory low back pain [5].

High impact information on RGS1

• CXCL12-induced chemotaxis and adhesion are impaired when FAK recruitment and phosphorylation are inhibited by either membrane cholesterol depletion or overexpression of RGS1 in progenitor B cells [6].
• To determine the signaling pathways that RGS1 may regulate, we examined the specificity of RGS1 for various G alpha subunits and assessed its effect on chemokine signaling [7].
• Regulator of G protein signaling 1 (RGS1) markedly impairs Gi alpha signaling responses of B lymphocytes [7].
• Furthermore, germinal center B lymphocytes, which are refractory to stromal-derived factor-1-triggered migration, express high levels of RGS1 [7].
• Functional studies demonstrated that RGS1 impairs platelet activating factor-mediated increases in intracellular Ca+2, stromal-derived factor-1-induced cell migration, and the induction of downstream signaling by a constitutively active form of G12 alpha [7].

Biological context of RGS1

• Using yeast strains harbouring a G(betagamma)-responsive FUS1-LacZ reporter gene, we demonstrate that heterologously expressed mammalian RGS1 also serves to decrease basal signalling in the absence of agonist [8].
• Analysis of a series of mutants spanning the entire N-terminal non-RGS region of RGS1 produced by conservative segment exchange (CSE) mutagenesis showed little loss of function in yeast [9].
• Enzyme kinetic analysis demonstrated that RGS1 increased both V(max) of the GTPase activity and the observed K(m) for GTP, consistent with RGS1 accelerating the rate of GTP hydrolysis of the chimeric G protein, whereas the agonist vasopressin accelerates guanine nucleotide exchange [10].
• Further characterization of the differentially expressed molecules, such as OX40 and RGS1, would provide useful information not only to elucidate the mechanism of ATL cell growth in vivo, but also to develop novel molecularly targeted therapies [11].
• Two full length BL34 cDNA were sequenced, and an open reading frame of 588 bp was identified that was predicted to encode for a 196 amino acid protein [3].

Anatomical context of RGS1

• We demonstrate here that RGS1 is expressed in human monocytes; by immunofluorescence and subcellular fractionation RGS1 was localized to the plasma membrane [12].
• RGS1, RGS2 and RGS16, other members of the R4 subfamily, were expressed in distinct progenitor and mature myeloerythroid and lymphoid lineage blood cells [13].
• To directly analyze the expression of BL34 mRNA in lymphoid tissues in situ, hybridization studies with human tonsil tissue sections were performed [3].
• In contrast, RNA from purified T cells treated with phytohemagglutinin and PMA had undetectable amounts of BL34 mRNA [3].

Associations of RGS1 with chemical compounds

• We found that RGS1 desensitizes a variety of chemotactic receptors including receptors for N-formyl-methionyl-leucyl-phenylalanine, leukotriene B4, and C5a [12].
• We mutated the equivalent serine residue in the family B/R4 RGS proteins RGS1 and RGS16 [14].
• Of a range of ligands studied, only haloperidol functioned as a neutral ligand in the presence of RGS1 [15].
• RGS1 enhanced vasopressin stimulation of V(2) receptor-G(i1)alpha/G(s)6alpha in a concentration-dependent manner [10].
• Here we present a detailed genetic analysis of ABA accumulation in detached and partially dehydrated rice leaves. using a population of F2 plants generated from the lowland x upland cross IR20 (high-ABA) x 63-83 (low-ABA) which was mapped with RFLP and AFLP markers [16].

Regulatory relationships of RGS1

• GIP-stimulated cAMP generation in control cells and in those coexpressing RGS1, -3, and -4 displayed a dose-dependent increase 10 min after GIP treatment [17].

Other interactions of RGS1

• These results indicate that RGS1 and RGS13 act together to regulate chemokine receptor signaling in human germinal center B lymphocytes and provide evidence that they contribute significantly to the rapid desensitization of the signaling pathway [1].
• RGS1 was also highly enriched in the lung, as was RGS2 and RGS16 [18].
• Expression of both genes increases in response to ConA, with RGS2 mRNA levels increasing briskly to a maximum between 0.5 and 1 hr and decreasing to baseline by 6 hr, whereas the RGS1 mRNA increase is delayed reaching a maximum between 1 and 2 hr [19].
• Of the five proteins, serine TADG-12 down-regulated under the detectable level after HMBA treatment, Rab-35, RGS1 and RFPL1 sharply up-regulated within the HMBA-induced BGC-823 cells, and GSG3, appearing in both treated and untreated cells, remarkably increased within BGC-823 cells after HMBA stimulation [20].
• RGS1 is a member of a protein family constituting a newly appreciated and large group of proteins that act as deactivators of G-protein signaling pathways by accelerating the GTPase activity of G-protein alpha subunits [12].

Analytical, diagnostic and therapeutic context of RGS1

• With reverse transcriptase polymerase chain reaction in addition mRNA of RGS1, 9, 12, 14 and 16 were detectable [21].
• Southern blot analysis of human DNA from various tissues and cells lines demonstrated that BL34 is a single-copy gene without evidence of rearrangement [3].
• Northern blot analysis performed with the BL34 cDNA revealed a 1.6-kb mRNA transcript that was present at low levels in RNA extracted from resting B lymphocytes, but whose expression was markedly increased in RNA prepared from mitogen-activated B cells [3].

References