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CD100 is a leukocyte semaphorin
S Delaire1, A Elhabazi, A Bensussan
1Unité INSERM U448, Faculté de médecine, Creteil, France. delair@im3.inserm.fr
Insights
CD100, a T lymphocyte activation molecule, associates with CD45 and a Ser/Thr kinase. As a semaphorin family member, CD100 suggests semaphorins may function beyond the nervous system in immunity.
Area of Science:
- Immunology
- Cell Biology
- Neuroscience
Background:
- CD100 is an activation molecule on human T lymphocytes.
- Its triggering induces costimulatory signals via distinct epitopes.
- CD100 associates with intracellular molecules in T cells.
Purpose of the Study:
- To detail the molecular interactions of CD100 in T cells.
- To explore the implications of CD100's classification within the semaphorin family.
- To investigate potential roles of semaphorins in non-nervous system physiology.
Main Methods:
- Analysis of CD100 association with CD45.
- Investigation of CD100 interaction with a Ser/Thr kinase.
- Review of CD100's classification within the semaphorin gene family.
Main Results:
- CD100 physically associates with CD45, impacting both molecules.
- CD100's cytoplasmic domain interacts with a Ser/Thr kinase.
- CD100 is identified as a member of the semaphorin gene family.
Conclusions:
- CD100 exhibits complex molecular associations within T cells.
- CD100's semaphorin identity suggests broader physiological roles for this protein family.
- Semaphorins may be involved in immune system regulation beyond their known neural functions.
Abstract:
CD100 was originally described as an activation molecule on the surface of human T lymphocytes. Its triggering through distinct epitopes leads to different signals of costimulation with phorbol myristate acetate (PMA) or with CD3 and CD2. Interestingly, CD100 was shown to associate with different partner molecules in T cells. First, CD100 can associate with CD45, a key molecule with protein tyrosine phosphatase activity involved in T-cell transduction: this association is physical and has functional consequences for both partners. Second, CD100 interacts in its cytoplasmic domain with a Ser/Thr kinase for which it represents a preferential substrate. Recently, CD100 was identified as a member of the semaphorin gene family. This family comprises approximately 20 structurally related proteins. The first semaphorins were identified in the developing nervous system. Function has been shown for only some of them and involves repulsion during growth cone guidance. Since CD100 was the first semaphorin identified in the immune system, this raises the possibility of the involvement of members of the semaphorin family in other physiological phenomena outside the nervous system.