C-type lectin
A C-type lectin is a type of carbohydrate-binding protein domain 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 7 subgroups based on the order of the various protein domains in each protein. This classification was subsequently updated in 2002, leading to seven additional groups. Most recently, three further subgroups were added.Group | Name | Associated domains |
I | Lecticans | EGF, Sushi, Ig and Link domains |
II | Asialoglycoprotein and DC receptors | - |
III | Collectins | - |
IV | Selectins | Sushi and EGF domains |
V | NK - cell receptors | - |
VI | Multi-CTLD endocytic receptors | FnII and Ricin domains |
VII | Reg group | - |
VIII | Chondrolectin, Layilin | - |
IX | Tetranectin | - |
X | Polycystin | WSC, REJ, PKD domains |
XI | Attractin | PSI, EGF and CUB domains |
XII | Eosinophil major basic protein | - |
XIII | DGCR2 | - |
XIV | Thrombomodulin, CD93, CD248, CLEC14A | EGF domains |
XV | Bimlec | - |
XVI | SEEC | SCP and EGF domains |
XVII | CBCP/Frem1/QBRICK | CSPG repeats and CalX-beta domains |
CLECs include:
- CLEC1A, CLEC1B
- CLEC2A, CLEC2B, CD69, CLEC2D, CLEC2L
- CLEC3A, CLEC3B
- CLEC4A, CLEC4C, CLEC4D, CLEC4E, CLEC4F, CLEC4G, ASGR1, ASGR2, FCER2, CD207, CD209, CLEC4M
- CLEC5A
- CLEC6A
- CLEC7A
- OLR1
- CLEC9A
- CLEC10A
- CLEC11A
- CLEC12A, CLEC12B
- CD302, LY75, PLA2R1, MRC1, MRC2
- CLEC14A
- CLEC16A
- CLEC17A
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