Homologous Superfamily

C-type lectin-like/link domain superfamily (IPR016186)

Short name: C-type_lectin-like/link_sf

Overlapping entries


Lectins occur in plants, animals, bacteria and viruses. Initially described for their carbohydrate-binding activity [PMID: 14533786], they are now recognised as a more diverse group of proteins, some of which are involved in protein-protein, protein-lipid or protein-nucleic acid interactions [PMID: 12223269]. There are at least twelve structural families of lectins, of which C-type (Ca+-dependent) lectins is one. C-type lectins can be further divided into seven subgroups based on additional non-lectin domains and gene structure: (I) hyalectans, (II) asialoglycoprotein receptors, (III) collectins, (IV) selectins, (V) NK group transmembrane receptors, (VI) macrophage mannose receptors, and (VII) simple (single domain) lectins [PMID: 15476922].

The term 'C-type lectin domain' was introduced to distinguish a carbohydrate-recognition domain (CRD) which is present in all Ca2+-dependent lectins, but not in other types of animal lectins. However, there are proteins with modules similar in overall structure to CRDs that serve functions other than sugar binding. Therefore, a more general term C-type lectin-like domain was introduced to refer to such domains, although both terms are sometimes used interchangeably [PMID: 16336259].

This superfamily represents a structural domain found in C-type lectins, as well as in other proteins, including:

  • The C-terminal domain of invasin [PMID: 10514372] and intimin [PMID: 10890451].
  • Link domain, which includes the Link module of tumor necrosis factor-inducible gene 6 protein (TSG-6) [PMID: 12972412] (a hyaladherin with important roles in inflammation and ovulation) and the hyaluronan binding domain of CD44 (which contains extra N-terminal beta-strand and C-terminal beta-hairpin) [PMID: 14992719]. The Link domain may have emerged as a result of a deletion of the long loop region from an ancestral canonical C-type lectin domain [PMID: 8690089].
  • Endostatin [PMID: 9724722] and the endostatin domain of collagen alpha 1 (XV) [PMID: 10966814], these domains being decorated with many insertions in the common fold.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.