Recombinant Human LSECtin/CLEC4G Protein, CF

LSECtin (liver and lymph node sinusoidal endothelial cell C-type lectin), also known as C-type lectin superfamily 4, member G (CLEC4G), is a member of subgroup II of the C-type (Ca²⁺-dependent) lectin superfamily (1). The protein was named LSECtin because its initial expression was described to be restricted to liver and lymph node sinusoidal endothelial cells (1). Since then, however, LSECtin has also been detected in peripheral blood and thymic dendritic cells isolated ex vivo, and in monocyte-derived macrophages and dendritic cells at the RNA and protein level (2). Human LSECtin is an approximately 40 kDa, single-pass, type II transmembrane glycoprotein that is 293 amino acids (aa) in length. It contains a short N-terminal cytoplasmic tail (aa 1-31) and a 21 aa transmembrane region. Its extracellular region consists of two N-linked glycosylation sites (aa 73 and 159), a coil-coil neck domain (aa 96-136), a C-type lectin-like domain (CTLD) of the type found in human
DC-SIGN and DC-SIGN receptor (aa 165-289), and a C-terminal Ca²⁺-dependent carbohydrate-recognition domain (C-type CRD) (1). Human LSECtin shares 64% aa sequence identity with mouse LSECtin. LSECtin binds to mannose, GlcNAc, and fucose in a Ca²⁺-dependent manner (1-3). In addition, LSECtin has the ability to bind to surface glycoproteins of enveloped viruses (3, 4). In particular, interaction of LSECtin with the surface glycoproteins of severe acute respiratory syndrome (SARS) coronavirus and Ebola virus has been described, and LSECtin-mediated infection of cells by Ebola virus has been demonstrated (3, 4).