SELL is a cell surface component that is a member of a family of adhesion/homing receptors that play important roles in lymphocyte-endothelial cell interactions. The molecule is composed of multiple domains: one homologous to lectins, one to epidermal growth factor, and two to the consensus repeat units found in C3/C4-binding proteins.
L-selectin acts as a "homing receptor" for lymphocytes to enter secondary lymphoid tissues via high endothelial venules. Ligands present on endothelial cells will bind to lymphocytes expressing L-selectin, slowing lymphocyte trafficking through the blood, and facilitating entry into a secondary lymphoid organ at that point. The receptor is commonly found on the cell surfaces of T cells. Naive T-lymphocytes, which have not yet encountered their specific antigen, need to enter secondary lymph nodes to encounter their antigen. Central memory T-lymphocytes, which have encountered antigen, express L-selectin to localize in secondary lymphoid organs. Here they reside ready to proliferate upon re-encountering antigen. Effector memory T-lymphocytes do not express L-selectin, as they circulate in the periphery and have immediate effector functions upon encountering antigen.
High expression of L-selectin on human bone marrow progenitor cells is an early sign of cells becoming committed to lymphoid differentiation.
L-selectin is also present on the surface of human embryo trophoblasts prior to implantation into the uterus. Similar to its function in lymphocytes, L-selectin acts as a receptor to facilitate adhesion of the embryo to the site of invasion on the surface epithelium of the uterine endometrium. The embryo secretes human chorionic gonadotropin (hCG), which downregulates anti-adhesion factor, MUC-1, located on the uterine epithelium at the site of invasion. Removal of MUC-1 exposes the oligosaccharide ligands of the uterine epithelium, thus allowing binding by the L-selectin receptor of the trophopblast cell, followed by embryo adhesion and invasion.
^Robbins SL, Cotran RS, Kumar V, Collins T (1998). Robbins Pathologic Basis of Disease. Philadelphia: W.B Saunders Company. ISBN0-7216-7335-X.
^Kohn LA, Hao QL, Sasidharan R, Parekh C, Ge S, Zhu Y, Mikkola HK, Crooks GM (October 2012). "Lymphoid priming in human bone marrow begins before expression of CD10 with upregulation of L-selectin". Nat. Immunol.13 (10): 963–71. doi:10.1038/ni.2405. PMID22941246.
^James JL, Carter AM, Chamley LW (May 2012). "Human placentation from nidation to 5 weeks of gestation. Part I: What do we know about formative placental development following implantation?". Placenta33 (5): 327–34. doi:10.1016/j.placenta.2012.01.020. PMID22374510.
Ord DC, Ernst TJ, Zhou LJ et al. (1990). "Structure of the gene encoding the human leukocyte adhesion molecule-1 (TQ1, Leu-8) of lymphocytes and neutrophils". J. Biol. Chem.265 (14): 7760–7. PMID1692315.
Bajorath J, Aruffo A (1995). "A template for generation and comparison of three-dimensional selectin models". Biochem. Biophys. Res. Commun.216 (3): 1018–23. doi:10.1006/bbrc.1995.2722. PMID7488174.
Dianzani U, Bragardo M, Buonfiglio D et al. (1995). "Modulation of CD4 lateral interaction with lymphocyte surface molecules induced by HIV-1 gp120". Eur. J. Immunol.25 (5): 1306–11. doi:10.1002/eji.1830250526. PMID7539755.
Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K et al. (1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene200 (1–2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID9373149.
Prakobphol A, Thomsson KA, Hansson GC et al. (1998). "Human low-molecular-weight salivary mucin expresses the sialyl lewisx determinant and has L-selectin ligand activity". Biochemistry37 (14): 4916–27. doi:10.1021/bi972612a. PMID9538010.