EXCEED THE SPACE PROVIDED. CAR is a junction adhesion molecule (JAM), similarto other known JAM proteins. These proteins generally localize to tight junctions, where they participate in cell-cell adhesion and link to cytoplasmic proteins.Several JAM proteins bind counter-receptors on leukocytes and participate in their transmigration across cell layers. JAM interactionswith most leukocyte types have been reported, except for B cells. New data show that CAR I binds B cells, thus establishing that JAM-leukocyte interactions include all major classes of white blood cells. I New data also show that CAR binds immunoglobulins.Details of these new CAR activities remain to be l elucidated. The long-term objective of this research is to identifythe molecular interactions in which CAR I participates and reach a more complete understanding of CAR function. In the sort-term, this projectwill I identifythe counter-receptor on B cells, cellular responses mediated by the CAR-B cell interaction, and the relationshipof CAR-immunoglobulin bindingto CAR function.
Specific Aim 1. Identifythe CAR counter-receptor present on B cells. Obtain cDNA for expression and isolationof recombinant protein.The B cell counter-receptor will be purifiedfrom Raji cells and identified by comparison of amino-terminal sequence Iwith protein and genetic databases, cDNA encoding the protein will be obtained from a repository (if the protein is known and the cDNA available) or by cloningde novo.
Specific Aim 2. Characterize the response of B cells following CAR binding.In isolated peripheral blood mononuclear cells, B cells express early markers of activation following bindingby CAR. Isolated B cells will be tested for responsiveness to CAR, and components essential for the response will identified. In addition, CAR may enhance B cell transmigrationthrough endothelial cell layers. CAR's role in leukocyte migration will be studied usingcells that express wild type and recombinant forms of CAR in a Transwell migration system.
Specific Aim 3. Characterize the CAR-immunoglobulin interaction. Specific domains of CAR and immunoglobulinsthat mediate their interactionwill be identifiedand mapped to determine their structural relationships to regions of these proteins known to participate in other interactions. Interactions between CAR binding immunoglobulins and the B cell counter receptor will identified.This work will advance knowledge of cells that form tight junctions and their interactionswith cells and molecules that must crossthose barriers. PERFORMANCE SITE ========================================Section End===========================================
| Carson, Steven D; Chapman, Nora M; Hafenstein, Susan et al. (2011) Variations of coxsackievirus B3 capsid primary structure, ligands, and stability are selected for in a coxsackievirus and adenovirus receptor-limited environment. J Virol 85:3306-14 |
| Carson, Steven D; Kim, Kyung-Soo; Pirruccello, Samuel J et al. (2007) Endogenous low-level expression of the coxsackievirus and adenovirus receptor enables coxsackievirus B3 infection of RD cells. J Gen Virol 88:3031-8 |
| Carson, Steven D (2004) Coxsackievirus and adenovirus receptor (CAR) is modified and shed in membrane vesicles. Biochemistry 43:8136-42 |
