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Regulation of L-selectin expression by membrane proximal proteolysis
T K Kishimoto1, J Kahn, G Migaki
1Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT 06877, USA.
Agents and Actions. Supplements
|January 1, 1995
Summary
L-selectin shedding from cell surfaces is a rapid process. Researchers identified a specific 6 kDa L-selectin transmembrane peptide (L-STMP), revealing the cleavage site between Lys321 and Ser322.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- L-selectin is a cell adhesion molecule on leukocytes.
- L-selectin shedding occurs upon activation or cross-linking.
- The mechanism of L-selectin shedding remained unclear.
Purpose of the Study:
- To investigate the mechanism of L-selectin down-regulation.
- To identify proteolytic fragments of L-selectin.
- To define the cleavage site of L-selectin.
Main Methods:
- Developed a trapping ELISA for soluble L-selectin detection.
- Produced polyclonal antisera against L-selectin domains.
- Used radiochemical sequencing to identify cleavage site.
Main Results:
- Identified a 6 kDa L-selectin transmembrane peptide (L-STMP).
- Determined the cleavage site occurs between Lys321 and Ser322.
- Common protease inhibitors did not affect L-selectin shedding.
Conclusions:
- L-selectin shedding involves specific proteolytic cleavage.
- The cleavage site is in the membrane-proximal extracellular domain.
- Further research can target this cleavage site for therapeutic interventions.