LSECtin

LSECtin is the acronym for "liver sinusoidal endothelial cell lectin". Like DC-SIGN and DC-SIGNR, LSECtin belongs to the family of C-type lectins. These are encoded by the lectin gene cluster on chromosome 19p13.3. They perform cell adhesion and pathogen recognition functions on dendritic cells, macrophages, liver cells and lymph node sinusoidal endothelial cells.

LSECtinis a type II Ca2+-dependent integral membrane protein with a size of approximately 40 kDa and a single C-type lectin-like domain at the COOH terminus that most closely resembles DC-SIGNR, DC-SIGN, and CD23 in homology (Liu D et al. 2019).

LSECtin interacts with mannose, NAcGlc and fucose and enables the recognition of pathogens, e.g. viruses, bacteria and allergens (Zhang F et al. 2014). LSECtin is also expressed on macrophages in both inflammatory and tumor processes.

LSECtin promotes the clearance of apoptotic cells by macrophages and induces the production of anti-inflammatory/tissue repair factors. For example, deletion of LSECtin leads to defective colonic macrophage function and impaired intestinal epithelial repair (Li Q et al. 2020). Furthermore, LSECtin is highly expressed on tumor-associated macrophages (TAMs).

The designation C-type comes from the fact that they require calcium for binding. Proteins containing C-type lectin domains have a variety of functions, including cell-cell adhesion, immune response to pathogens, and apoptosis.

1. Li Q et al. (2020) Activation of mTORC1 by LSECtin in macrophages directs intestinal repair in inflammatory bowel disease. Cell Death Dis 11:918.
2. Liu D et al. (2019) LSECtin on tumor-associated macrophages enhances breast cancer stemness via interaction with its receptor BTN3A3. Cell Res 29:365-378.
3. Pandey E et al (2020) Prominent Receptors of Liver Sinusoidal Endothelial Cells in Liver Homeostasis and Disease. Front Physiol. 11:873.
4. Zhang F et al (2014) DC-SIGN, DC-SIGNR and LSECtin: C-type lectins for infection. Int Rev Immunol 33:54-66.