|Functions of animal and human lectinsa|
|Activity||Example of lectin|
|Recognition of stem region of N-glycans, a signal for ubiquitin conjugation when accessible in incorrectly folded glycoproteins||F-box proteins Fbs1 and Fbs2, which comprise the ligand-specific part of SCFb ubiquitin ligase complexes|
|Molecular chaperones with dual specificity for Glc2/Glc1Man9GlcNAc2 and protein part of nascent glycoproteins in the ER||Malectin/ribophorin I complex, calnexin, calreticulin|
|Targeting of misfolded glycoproteins with Man8-5GlcNAc2 as carbohydrate ligand to ER-associated degradation (ERAD)||EDEM1,2c/Mnl1 (Htm1) (lectins or glycosidases?), Yos9p (MRHd domain) in yeast, erlectin (XTP3-Be) and OS-9f in mammals|
|Intracellular routing of glycoproteins and vesicles and apical delivery||Comitin, ERGIC53g and VIP36h (probably also ERGLi and VIPLj), galectins-3, -4 and -9, P-type lectins|
|Intracellular transport and extracellular assembly||Non-integrin 67 kDa elastin/laminin-binding protein|
|Enamel formation and biomineralization||Amelogenin|
|Inducer of membrane superimposition and zippering (formation of Birbeck granules)||Langerin (CD207)|
|Cell type-specific endocytosis||Cysteine-rich domain (β-trefoil) of the dimeric form of mannose receptor for GalNAc-4-SO4-bearing glycoprotein hormones in hepatic endothelial cells, dendritic cell and macrophage C-type lectins (mannose receptor family members (tandem-repeat type) and single-CRDk lectins such as trimeric langerin/CD207 or tetrameric DC-SIGNl/CD209), hepatic and macrophage asialoglycoprotein receptors, HAREm, P-type lectins|
|Recognition of foreign glycans (β1,3-glucans, cell wall peptidoglycan, LOSn and LPSo), mycobacterial glycolipid or host-like epitopes||CR3p (CD11b/CD18, Mac-1 antigen), C-type lectins such as collectins, DC-SIGN, dectin-1, Mincle and RegIIIγ (murine)q or HIP/PAP (human), ficolins, galectins, immulectins, intelectins, Limulus coagulation factors C and G, siglecs, tachylectins|
|Recognition of foreign or aberrant glycosignatures on cells (including endocytosis or initiation of opsonization or complement activation) and of apoptotic/necrotic cells (glycans or peptide motifs)||Collectins, C-type macrophage and dendritic cell lectins, CR3 (CD11b/CD18, Mac-1 antigen), α/Θ-defensins, ficolins, galectins, pentraxins (CRP, limulin), RegIIIγ (HIP/PAP), siglecs, tachylectins|
|Targeting of enzymatic activity in multimodular proteins||Acrosin, Limulus coagulation factor C, laforin, β-trefoil fold ((QxW)3 domain) of GalNAc-Tsr involved in mucin-type O-glycosylation, frequent in microbial glycosylhydrolases for plant cell wall polysaccharides, termed carbohydrate-binding modules|
|Bridging of molecules||Cerebellar soluble lectin, cytokines (e.g. IL-2s–IL-2R and CD3 of TCR), galectins|
|Induction or suppression of effector release (H2O2, cytokines etc.)||Chitinase-like YKL-40, galectins, I-type lectins (e.g. CD33 (siglec-3), siglecs-7 and -9), selectins and other C-type lectins such as CD23, BDCA2 and dectin-1, Toll-like receptor 4|
|Alteration of enzymatic activities in modular proteins/receptor endocytosis via lattice formation||Mannan-binding lectin (acting on meprins); galectins|
|Cell growth control, induction of apoptosis/anoikis and axonal regeneration||Amphoterin and other heparin-binding proteins, cerebellar soluble lectin, chitinase-like lectins, C-type lectins, galectins, hyaluronic acid-binding proteins, siglecs (e.g. CD22 and CD33)|
|Cell migration and routing||Galectins, hyaluronic acid-binding proteins (CD44, hyalectans/lecticans, RHAMMt), I-type lectins, selectins and other C-type lectins|
|Cell–cell interactions||Galectins, gliolectin, I-type lectins (e.g. siglecs, N-CAMu, P0 or L1), selectins and other C-type lectins such as DC-SIGN or macrophage mannose receptor|
|Cell–matrix interactions||Calreticulin, discoidin I, galectins, heparin- and hyaluronic acid-binding lectins including hyalectans/lecticans|
|Matrix network assembly||Galectins (e.g. galectin-3/hensin), non-integrin 67 kDa elastin/laminin-binding protein, proteoglycan core proteins (C-type CRD and G1 domain of hyalectans/lecticans)|
aadapted from , with permission, and extended.
bSkp-1-Cul1-F-box protein complex.
cER degradation enhancing α-mannosidase-like protein.
dmannose-6-phosphate receptor homology.
eXTP3-transactivated gene B precursor.
gER-Golgi intermediate compartment protein (lectin) (MW: 53 kDa).
hvesicular-integral (membrane) protein (lectin) (MW: 36 kDa).
kcarbohydrate recognition domain.
ldendritic cell-specific ICAM-3-grabbing nonintegrin.
mhyaluronan receptor for endocytosis.
pcomplement receptor type 3.
qmember of regenerating (reg) gene family of secreted proteins.
treceptor for hyaluronan-mediated motility.
uneural cell adhesion molecule.
Gabius and Kayser
Gabius and Kayser Diagnostic Pathology 2014 9:4 doi:10.1186/1746-1596-9-4