The evidence for the IL-2 receptor beta chain processing from p70 to p75.
The biosynthesis of human interleukin 2 receptor (IL-2R)p75 was studied with TU27 monoclonal antibody (TU27 mAb) specific for the IL-2Rp75. TU27 mAb specifically immunoprecipitated not only p75 with a mol. wt of 70-82 kd and an isoelectric point (pl) of 4.4-4.7 but also p70 with a mol. wt of 70 kd and a pl of 4.7 from the cell lysate of MT-2, a human T cell line constitutively expressing IL-2R, labeled metabolically with [35S]cysteine. In contrast, only p75 was detected when the lysate of MT-2 cells surface-labeled with Na125I was immunoprecipitated with TU27 mAb. These results suggest that p75 is a mature form of IL-2Rp75 expressed on the cell surface. Pulse-chase experiments demonstrated that p70 could be converted into IL-2Rp75 by post-translational processing. Studies with monensin, endoglycosidase F, and neuraminidase showed that the mature IL-2Rp75 molecule is generated through N-linked glycosylation and sialylation of the p70 precursor.
Asao
H
H
Department of Microbiology, Tohoku University School of Medicine, Sendai, Japan.
Takeshita
T
T
Nakamura
M
M
Nagata
K
K
Sugamura
K
K
D000911:Antibodies, Monoclonal; D002460:Cell Line; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006031:Glycosylation; D006801:Humans; D007526:Isoelectric Point; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008970:Molecular Weight; D008985:Monensin / Q000494:pharmacology; D009439:Neuraminidase / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D015375:Receptors, Interleukin-2 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015375:Receptors, Interleukin-2; D012794:Sialic Acids; D008985:Monensin; D006026:Glycoside Hydrolases; D009439:Neuraminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase