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Carboxyl terminal sequence of human phospholipase Cgamma2
F Ozdener1, S P Kunapuli, J L Daniel
1Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA. fozdener@astro.temple.edu
Platelets
|April 12, 2001
Summary
Researchers identified a new sequence for human phospholipase Cgamma2 (PLCgamma2), revealing potential phosphorylation sites crucial for platelet activation by collagen. This finding clarifies PLCgamma2
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Signaling
Background:
- Phospholipase Cgamma2 (PLCgamma2) is a key enzyme in platelet activation.
- Collagen stimulation induces tyrosine phosphorylation of PLCgamma2, but specific sites remain unknown.
- Previous human PLCgamma2 cDNA sequences may contain errors affecting protein structure.
Purpose of the Study:
- To determine the correct 3' terminal cDNA sequence of human PLCgamma2.
- To identify potential tyrosine phosphorylation sites in the carboxyl terminus of PLCgamma2.
- To clarify the molecular mechanisms of collagen-induced platelet activation.
Main Methods:
- Sequencing of the 3' terminal cDNA of human PLCgamma2.
- Comparison of the newly obtained sequence with previously reported sequences.
- Deduction of the carboxyl-terminal amino acid sequence and identification of tyrosine residues.
Main Results:
- A discrepancy was found in the human PLCgamma2 cDNA sequence, specifically an extra guanosine at position 3723, causing a reading frame shift.
- The revised carboxyl-terminal amino acid sequence shows 88% identity to rat PLCgamma2, significantly higher than the published sequence (26% identity).
- Two tyrosine residues at positions 1245 and 1264 were identified in the new deduced sequence, representing potential phosphorylation sites.
Conclusions:
- The corrected human PLCgamma2 cDNA sequence provides a more accurate representation of the protein's carboxyl terminus.
- The identified tyrosine residues (1245 and 1264) are potential phosphorylation sites critical for PLCgamma2 activation.
- These findings contribute to understanding the role of PLCgamma2 in collagen-mediated platelet signaling and activation.