Differential expression of a novel protein kinase in human B lymphocytes. Preferential localization in the germinal center

• Published in: The Journal of biological chemistry Vol. 269; no. 24; pp. 16802 - 16809
• Main Authors: KATZ, P, WHALEN, G, KEHRL, J. H
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 17.06.1994
• Subjects: 3T3 Cells; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Antigens, CD - biosynthesis; B-Lymphocytes - enzymology; Base Sequence; Biological and medical sciences; Carrier Proteins - biosynthesis; Cell Line; Chlorocebus aethiops; Cloning, Molecular; DNA, Complementary - isolation & purification; Drosophila - genetics; Drosophila Proteins; Enzymes and enzyme inhibitors; Eye Proteins - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression; GTP-Binding Proteins - genetics; Humans; Hyaluronan Receptors; In Situ Hybridization; Intracellular Signaling Peptides and Proteins; MAP Kinase Kinase Kinases; Mice; Molecular Sequence Data; Myosin Heavy Chains; Myosins - genetics; Polymerase Chain Reaction; Protein Biosynthesis; Protein Kinases - biosynthesis; Protein Kinases - genetics; Protein-Serine-Threonine Kinases - genetics; Receptors, Cell Surface - biosynthesis; Receptors, Lymphocyte Homing - biosynthesis; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; Sequence Deletion; Sequence Homology, Amino Acid; Transcription, Genetic; Transfection; Transferases; Human; Molecular hybridization; Enzymatic activity; Enzyme; Protein kinase; Transferases; In situ; Primary structure; B-Lymphocyte; Germinal cell; Molecular cloning; Gene expression
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)89463-2

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.