3wh2
Human Mincle in complex with citrate
Structural highlights
FunctionCLC4E_HUMAN C-type lectin that functions as cell-surface receptor for a wide variety of ligands such as damaged cells, fungi and mycobacteria. Plays a role in the recognition of pathogenic fungi, such as Candida albicans. The detection of mycobacteria is via trehalose 6,6'-dimycolate (TDM), a cell wall glycolipid. Specifically recognizes alpha-mannose residues on pathogenic fungi of the genus Malassezia. Recognizes also SAP130, a nuclear protein, that is released by dead or dying cells. Transduces signals through an ITAM-containing adapter protein, Fc receptor gamma chain /FCER1G. Induces secretion of inflammatory cytokines through a pathway that depends on SYK, CARD9 and NF-kappa-B. Publication Abstract from PubMedMincle [macrophage inducible Ca2+-dependent (C-type) lectin; CLEC4E] and MCL (macrophage C-type lectin; CLEC4D) are receptors for the cord factor TDM (trehalose-6,6'-dimycolate), a unique glycolipid of mycobacterial cell-surface components, and activate immune cells to confer adjuvant activity. Although it is known that receptor-TDM interactions require both sugar and lipid moieties of TDM, the mechanisms of glycolipid recognition by Mincle and MCL remain unclear. We here report the crystal structures of Mincle, MCL, and the Mincle-citric acid complex. The structures revealed that these receptors are capable of interacting with sugar in a Ca2+-dependent manner, as observed in other C-type lectins. However, Mincle and MCL uniquely possess shallow hydrophobic regions found adjacent to their putative sugar binding sites, which reasonably locate for recognition of fatty acid moieties of glycolipids. Functional studies using mutant receptors as well as glycolipid ligands support this deduced binding mode. These results give insight into the molecular mechanism of glycolipid recognition through C-type lectin receptors, which may provide clues to rational design for effective adjuvants. Structural analysis for glycolipid recognition by the C-type lectins Mincle and MCL.,Furukawa A, Kamishikiryo J, Mori D, Toyonaga K, Okabe Y, Toji A, Kanda R, Miyake Y, Ose T, Yamasaki S, Maenaka K Proc Natl Acad Sci U S A. 2013 Oct 7. PMID:24101491[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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