title: G alpha 16, a G protein alpha subunit specifically expressed in hematopoietic cells.
abstract: Signal-transduction pathways mediated by guanine nucleotide-binding regulatory proteins (G proteins) determine many of the responses of hematopoietic cells. A recently identified gene encoding a G protein alpha subunit, G alpha 16, is specifically expressed in human cells of the hematopoietic lineage. The G alpha 16 cDNA encodes a protein with predicted Mr of 43,500, which resembles the G q class of alpha subunits and does not include a pertussis toxin ADP-ribosylation site. In comparison with other G protein alpha subunits, the G alpha 16 predicted protein has distinctive amino acid sequences in the amino terminus, the region A guanine nucleotide-binding domain, and in the carboxyl-terminal third of the protein. Cell lines of myelomonocytic and T-cell phenotype express the G alpha 16 gene, but no expression is detectable in two B-cell lines or in nonhematopoietic cell lines. G alpha 16 gene expression is down-regulated in HL-60 cells induced to differentiate to neutrophils with dimethyl sulfoxide. Antisera generated from synthetic peptides that correspond to two regions of G alpha 16 specifically react with a protein of 42- to 43-kDa in bacterial strains that overexpress G alpha 16 and in HL-60 membranes. This protein is decreased in membranes from dimethyl sulfoxide-differentiated HL-60 cells and is not detectable in COS cell membranes. The restricted expression of this gene suggests that G alpha 16 regulates cell-type-specific signal-transduction pathways, which are not inhibited by pertussis toxin.
authors.affiliation: Division of Biology 147-75, California Institute of Technology, Pasadena 91125.
authors.forename: T T
authors.initials: TT
authors.lastname: Amatruda
authors.forename: D A
authors.initials: DA
authors.lastname: Steele
authors.forename: V Z
authors.initials: VZ
authors.lastname: Slepak
authors.forename: M I
authors.initials: MI
authors.lastname: Simon
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D019204:GTP-Binding Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D004247:DNA; D019204:GTP-Binding Proteins