The smallest of the vascular selectins, a 74-100 kDa molecule, is constitutively expressed at the tips of microfolds on granulocytes, monocytes, and a vast array of circulating lymphocytes. L-selectin is also known as LECAM-1, LAM-1, Mel-14 antigen, gp90 mel, and Leu8/TQ-1 antigen. L-selectin is important for lymphocyte homing and adhesion to high endothelial cells of post capillary venules of peripheral lymph nodes. Moreover, this adhesion molecule contributes greatly to the capture of leukocytes during the early phases of the adhesion cascade. Following capture, L-selectin is shed from the leukocyte surface after chemoattractant stimulation. L-selectin interacts with three known counter receptors or ligands, MAdCAM-1, GlyCAM-1, and CD34. In conjunction with other molecules, L-selectin's function and influence in the adhesion cascade has been under scrutiny in many experiments using gene-targeted mice.

In L-selectin deficient mice, trauma-induced leukocyte rolling in mesentary or cremaster muscle veules is normal initially, but declines over time. Using an intravenous L-selectin antibody, this phenotype can be reproduced, thus blocking the function of L-selectin. This indicates that trauma-inducted rolling in these mice is P-selectin dependent with a velocity highly comparable to that observed in wild-type mice. L-selectin is critical in mediating rolling after surgical trauma and is necessary for neutrophil recruitment after inflammation. Nevertheless, basal neutrophil trafficking appears to remain unaffected by absence of L-selectin since peripheral leukocyte and neutrophil counts in these mice were normal.

In TNF-α, tumor necrosis factor-alpha, treated mice deficient in L-selectin, data suggests that leukocyte rolling is P-selectin dependent. The lack of L-selectin in these mice reduces the efficiency of E-selectin mediated rolling is shown by the sensitivity of rolling to P-selectin antibodies. These experiments consistently show that L- and P-selectin mediate leukocyte rolling, however, L-selectin alone cannot assume this task at normal velocities in vivo. L- and P- selectin cooperate in such a way that in the absence of P-selectin, L-selectin must initiate leukocyte interactions to allow slow rolling on E-selectin. In addition, L- or P-selectin must be present to mediate capture before the commencement of leukocyte rolling. Without the presence of either L- or P-selectin, rolling cannot occur.

Theoretical 3-D model of L-selectin (the C-type lectin domain, and residues 1-120). This 3-D structure is viewed using RasMol. Left-clicking on the molecule allows change in orientation, and right-clicking on the molecule gives options for different display modes.

To view the molecule using a different program, or to find out more information on the structure, choose P-selectin from the list of 3-D Structures of Selectins.

View various information about this molecule at the National Center for Biotechnology Information.


Search similar protein and nucleotide sequences between various species using BLAST (Basic Local Alignment Search Tool)
  • Copy the desired sequence from the GenBank Database and paste it into the text box on the BLAST page.
  • Search results will provide a list of homologous molecules and show a statistical relationship between high-scoring segment pairs.
  • For more information on the results, consult the BLAST Help Manual.


Read the following categorized abstracts or link to Medline to conduct your own query.

  • Cloning of the human gene: Isolation and chromosomal localization of cDNAs encoding a novel human lymphocyte cell surface molecule, LAM-1: homology with the mouse lymphocyte homing receptor and other human adhesion proteins.
  • Cloning of the murine gene: Mouse lymph node homing receptor cDNA clone encodes a glycoprotein revealing tandem interaction domains.
  • Potential disease relevance: Dual binding capacity of mucosal immunoblasts to mucosal and synovial endothelium in humans: dissection of the molecular mechanisms.
  • Microcirculation-based publication: Sequential contribution of L- and P-selectin to leukocyte rolling in vivo.
  • Other: Neutrophil Mac-1 and MEL-14 adhesion proteins inversely regulated by chemotactic factors.

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