Molecular cloning of gp42, a cell-surface molecule that is selectively induced on rat natural killer cells by interleukin 2: glycolipid membrane anchoring and capacity for transmembrane signaling.
We have previously shown that in vitro culture of rat natural killer (NK) cells in high concentrations of recombinant interleukin 2 (rIL-2) leads to the expression of a surface glycoprotein with a molecular mass of approximately 42 kD. This glycoprotein, gp42, is not induced on other lymphocytes and thus provides a lineage-specific marker for rIL-2-activated NK cells. We here present the nucleotide sequence for gp42 cDNA. The open reading frame encodes 233 amino acids with three potential sites for N-linked glycosylation. The deduced amino acid sequence lacks an apparent transmembrane domain and instead contains a hydrophobic COOH terminus that is characteristic of glycosylphosphatidylinositol (GPI)-anchored surface proteins. Consistent with this, gp42 is cleaved from the NK-like cell line, RNK-16, by phosphatidylinositol-specific phospholipase C (PI-PLC), as is gp42 expressed on CHO cells that have been transformed with gp42 cDNA. On rIL-2-activated NK cells, gp42 is resistant to PI-PLC, though our studies suggest that gp42 on these cells is still expressed as a GPI-anchored molecule. Antibody to gp42 stimulates in RNK-16 cells an increase in inositol phosphates and in intracellular calciu, signals that are associated with the activation of lymphocytes, including NK cells. rIL-2-activated NK cells, however, lack this response to gp42 as well as to other stimuli. Thus, gp42, the only NK-specific activation antigen, is a GPI-anchored surface molecule with the capacity to stimulate transmembrane signaling.
Seaman
W E
WE
Arthritis/Immunology Section, Veterans Administration Medical Center, San Francisco, California.
Niemi
E C
EC
Stark
M R
MR
Goldfien
R D
RD
Pollock
A S
AS
Imboden
J B
JB
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D006017:Glycolipids / Q000502:physiology; D017261:Glycosylphosphatidylinositols; D007376:Interleukin-2 / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010716:Phosphatidylinositols / Q000378:metabolism / Q000502:physiology; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases; D051381:Rats; D015398:Signal Transduction / Q000276:immunology; D014162:Transfection
D000911:Antibodies, Monoclonal; D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D010716:Phosphatidylinositols; C066698:membrane glycoprotein gp42, rat NK cell; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D002118:Calcium