A C-type lectin (CLEC) is a type of carbohydrate-binding protein known as a lectin. The C-type designation is from their requirement for calcium for binding. Proteins that contain C-type lectin domains have a diverse range of functions including cell-cell adhesion, immune response to pathogens and apoptosis.
Classification
Drickamer et al. classified C-type lectins into seven subgroups (I to VII) based on the order of the various protein domains in each protein. This classification was subsequently updated in 2002, leading to seven additional groups (VIII to XIV). Most recently, three further subgroups were added (XV to XVII).
Group Name Associated domains I Lecticans EGF, Sushi, Ig and Link domains II Asialoglycoprotein and DC receptors None III Collectins None IV Selectins Sushi and EGF domains V NK - cell receptors None VI Multi-CTLD endocytic receptors FnII and Ricin domains VII Reg group None VIII Chondrolectin, Layilin None IX Tetranectin None X Polycystin WSC, REJ, PKD domains XI Attractin (ATRN) PSI, EGF and CUB domains XII Eosinophil major basic protein (EMBP) None XIII DGCR2 None XIV Thrombomodulin, CD93, CD248, CLEC14A EGF domains XV Bimlec None XVI SEEC SCP and EGF domains XVII CBCP/Frem1/QBRICK CSPG repeats and CalX-beta domains
CLECs include:
CLEC1A, CLEC1B CLEC2A, CLEC2B, CD69 (CLEC2C), CLEC2D, CLEC2L CLEC3A, CLEC3B CLEC4A, CLEC4C, CLEC4D, CLEC4E, CLEC4F, CLEC4G, ASGR1 (CLEC4H1), ASGR2 (CLEC4H2), FCER2 (CLEC4J), CD207 (CLEC4K), CD209 (CLEC4L), CLEC4M CLEC5A CLEC6A CLEC7A OLR1 (CLEC8A) CLEC9A CLEC10A CLEC11A CLEC12A, CLEC12B CD302 (CLEC13A), LY75 (CLEC13B), PLA2R1 (CLEC13C), MRC1 (CLEC13D), MRC2 (CLEC13E) CLEC14A CLEC16A CLEC17A
The "NK Cell lectin-like receptors" are a very closely related group: KLRA1 KLRB1 (CLEC5B) KLRC1, KLRC2, KLRC3, KLRC4 KLRD1 KLRF1 (CLEC5C) KLRG1 (CLEC15A), KLRG2 (CLEC15B) KLRK1
Additional proteins containing this domain include:
AGC1; ATRNL1 BCAN CD248; CD72; CD93; CHODL; CL-K1-Ia; CL-K1-Ib; CL-K1-Ic; CLECSF5; COLEC10; COLEC11; COLEC12; CSPG3 FCER2; FREM1; HBXBP; LAYN; LOC348174; LOC728276 MAFA; MBL2; MGC34761; MICL; MRC1L1 OLR1 PAP; PKD1; PKD1L2; PLA2R1; PRG2; PRG3 REG1A; REG1B; REG3A; REG3G; REG4 SELE; SELL; SELP; SFTPA1; SFTPA2; SFTPA2B; SFTPD; SRCL THBD VCAN
References
External links Functional Glycomics Gateway, a collaboration between the Consortium for Functional Glycomics and Nature Publishing Group