title: Differential expression of a novel protein kinase in human B lymphocytes. Preferential localization in the germinal center.
abstract: B lymphocytes which reside in the germinal center region of lymphoid follicles are functionally and phenotypically distinct from the surrounding mantle zone B cells. We have isolated cDNA clones for several genes that are differentially expressed between these two populations of B lymphocytes. One such gene, BL44, is preferentially expressed in germinal center B cells. The nucleotide sequence of a 2,874-base pair BL44 cDNA was determined and a 2,451-bp open reading frame found that encodes for a 97-kDa serine/threonine protein kinase referred to as GC kinase. It has an NH2-terminal catalytic domain most similar to that of the Drosophila NinaC protein and the yeast STE20 protein. GC kinase mRNA transcripts are not unique to germinal center B cells and are found in several other tissues, including brain, lung, and placenta. The GC kinase protein was immunoprecipitated from transfected COS cells and from the Burkitt cell line RAMOS. GC kinase immunoprecipitated from transfected COS cells phosphorylated the substrates casein and myelin basic protein. In addition, a 97-kDa phosphoprotein likely to be GC kinase itself was detected. GC kinase may participate in an important signal transduction pathway in germinal center B cells.
authors.affiliation: Laboratory of Immunoregulation, NIAID, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: P
authors.initials: P
authors.lastname: Katz
authors.forename: G
authors.initials: G
authors.lastname: Whalen
authors.forename: J H
authors.initials: JH
authors.lastname: Kehrl
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000201:enzymology*; D001483:Base Sequence; D002352:Carrier Proteins / Q000096:biosynthesis*; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000302:isolation & purification; D004330:Drosophila / Q000235:genetics; D029721:Drosophila Proteins; D005136:Eye Proteins / Q000235:genetics; D019204:GTP-Binding Proteins / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D018960:Hyaluronan Receptors; D017403:In Situ Hybridization; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D051379:Mice; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains; D009218:Myosins / Q000235:genetics; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011494:Protein Kinases / Q000096:biosynthesis* / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D016201:Receptors, Lymphocyte Homing / Q000096:biosynthesis*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014162:Transfection; D000099317:Hippo Kinases
chemical_list: D015703:Antigens, CD; D002352:Carrier Proteins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D005136:Eye Proteins; D019204:GTP-Binding Proteins; D018960:Hyaluronan Receptors; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D018995:Myosin Heavy Chains; D009218:Myosins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011956:Receptors, Cell Surface; D016201:Receptors, Lymphocyte Homing; D029701:Saccharomyces cerevisiae Proteins; C499474:hpo protein, Drosophila; D000099317:Hippo Kinases; C078754:STE20 protein, S cerevisiae; C072308:ninaC protein, Drosophila