Increases in Tyrosine Phosphorylation Are Detectable before Phospholipase C Activation after T Cell Receptor Stimulation
Abstract
Antiphosphotyrosine immunoblots were used to characterize tyrosine phosphorylated proteins after stimulation of the human T Cell Receptor (TCR). Increased tyrosine phosphorylation was evident on at least 12 substrates within 2 min after ligation of the TCR with Monoclonal antibody. Analysis of the time course for increased tyrosine phosphorylation revealed distinct patterns. Increased phosphorylation of 135-kDa and 100-kDa substrates was evident within 5 s, whereas increased phosphorylation of the TCR-zeta-chain required several minutes after treatment with anti-CD3 mAb. This rapid cellular tyrosine phosphorylation occurred independent of the cell cycle, as it occurred after stimulation of resting T cells, T cell blasts, and the Jurkat T cell leukemia line. When the TCR complex was cross-linked together with the CD4 receptor by heteroconjugate anti-CD3/CD4 mAb, an increased magnitude of tyrosine phosphorylation occurred, although no new substrates could be detected. These findings show that increased tyrosine phosphorylation is the earliest yet detected signal observed after ligation of the TCR complex, and furthermore suggest that tyrosine phosphorylation might link the TCR to the phosphatidylinositolbisphosphate hydrolysis signaling pathway. Reprints.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1990
- Accession Number
- ADA220027
Entities
People
- Carl H. June
- Jeffrey A. Ledbetter
- Lawrence E. Samelson
- Mary C. Fletcher
Organizations
- Naval Medical Research Center