Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.2.1.7 (BAL)
 1,977 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Engagement of membrane IgM on a number of human and murine B-cell lines induced activation of a Mn(2+)-preferring serine/threonine kinase that phosphorylated microtubule-associated protein-2 (MAP-2) in vitro. B-cell MAP-2 kinase (MAP-2K) activity could be fractionated into two peaks by sequential DEAE and hydrophobic chromatography. Although peak I included two tyrosine phosphoproteins of molecular mass 36 and 38 kDa, peak II showed a single 42-kDa tyrosine phosphoprotein (pp42). Since all kinase activity could be removed from peak II material over an antiphosphotyrosine immune affinity column, it suggests that pp42 is identical with lymphoid MAP-2K. Although peak I activity showed a similarity to peak II with regard to its preference for Mn2+, sensitivity to phosphatase exposure, and resistance to a range of common serine kinase inhibitors, it is not clear whether these activities are related. MAP-2 kinase activity could also be induced by treatment with the phorbol ester, phorbol myristate 13-acetate, suggesting that protein kinase C may also be involved with MAP-2K regulation. Although MAP-2K activity reached a peak response within minutes of receptor ligation, there were differences in the rates of dephosphorylation of pp42 and decline of MAP-2K activity in different B-cell lines. The tyrosine phosphatase inhibitor, vanadate, transformed a rapidly reversible MAP-2K response in BAL 17.2 cells into a sustained state of activation that resembled the kinetics of activation in WEHI-231 cells. The latter finding implies involvement of a tyrosine phosphatase, which opposes the effect of an inducing tyrosine kinase.
 ...
PMID:Stimulation of B-cells via the membrane immunoglobulin receptor or with phorbol myristate 13-acetate induces tyrosine phosphorylation and activation of a 42-kDa microtubule-associated protein-2 kinase. 165 69

The regulation and function of CREB was examined in B cells to begin to elucidate the role of cAMP-derived signals in B cell activation. CRE-binding activity detected by the electrophoretic mobility shift assay was found to be constitutively expressed in nuclear extracts of primary murine splenic B cells and was unchanged in nuclear extracts obtained from B cells stimulated in a variety of ways. This activity was shown to be specific by competition analysis and to represent CREB or a closely related molecule on the basis of a "supershift" in the mobility of the nucleoprotein complex induced by anti-CREB antiserum. The function of B cell CREB was assessed by transient transfection of the murine B lymphoma cell line, BAL-17, with a CRE-dependent chloramphenicol acetyl-transferase (CAT) construct that contains a portion of the somatostatin promoter. Cross-linking of the surface Ig receptors of transfected BAL-17 B cells produced a threefold induction of CAT activity. Forskolin, which markedly induced CAT expression in PC12 cells transfected with the CRE-dependent construct, failed to stimulate CAT activity in transfected BAL-17 B cells despite an increase in cAMP. However, anti-Ig was found to act in synergy with forskolin to produce enhanced CAT activity. A phosphoprotein of appropriate molecular size for CREB was immunoprecipitated from anti-Ig plus forskolin treated BAL-17 B cells. These results suggest that CREB is present in primary B cells and that CRE-dependent gene expression is regulated by surface Ig either alone or in synergy with cAMP; the latter implies cross-talk between intracellular signaling pathways acting at the level of CREB.
 ...
PMID:Induction of CREB activity via the surface Ig receptor of B cells. 839 39

Varicella-zoster virus (VZV) ORF61 encodes a phosphoprotein that transactivates VZV promoters. Transfection of cells with cosmid DNAs, including a cosmid with a large deletion in ORF61, resulted in a VZV ORF61 deletion mutant that was impaired for growth in vitro and could be partially complemented by growth in neuroblastoma or osteosarcoma cell lines. Cells infected with the VZV ORF61 deletion mutant expressed normal levels of an immediate-early VZV protein, but had reduced levels of a late protein and showed abnormal syncytia. Carboxy terminal truncation mutants of VZV ORF61 protein have a transrepressing phenotype and inhibit the infectivity of cotransfected wild-type viral DNA. Transfection of cells with cosmid DNAs, including a cosmid with stop codons that should result in an ORF61 truncation mutant expressing a transrepressing protein that retains the RING finger domain, resulted in a viral genome which reverted back to the wild-type sequence. BAL-31 exonuclease was used to produce deletions at the site of the stop codons in ORF61 of the cosmid, resulting in loss of the RING finger domain. Transfection of tissue culture cells with the ORF61 BAL-31 deletion mutants and other cosmid DNAs yielded viable viruses. Thus, while deletion mutants lacking the RING finger domain of ORF61 replicate in cell culture, a mutant with stop codons that retains this domain could not be propagated and reverted to wild-type virus.
 ...
PMID:Varicella-zoster virus ORF61 deletion mutants replicate in cell culture, but a mutant with stop codons in ORF61 reverts to wild-type virus. 965 49