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74  structures 5447  species 0  interactions 28430  sequences 673  architectures

Clan: CAP (CL0659)


Cysteine-rich secretory proteins Add an annotation

This is a highly evolutionary diversified protein superfamily whose members share specific sequence motifs. For the mammalian members, roles in reproduction, development, immune function and several pathologies have been proposed. Ant and wasp allergens, snake venom toxins and plant antifungal proteins are included in this superfamily data suggest that CAP proteins participate in various biological activities across phyla. Several signature sequences characterize mammalian members of the superfamily: CAP1-2 and CAP3-4, variable Cys-rich hinge regions and Ct extensions. Mammalian CAPs include nine subfamilies: cysteine rich secretory proteins (CRISPs), glioma pathogenesis related-1 (GLIPR1), glioma pathogenesis related-2 (GLIPR2)/Golgi, associated pathogenesis related-1 (GAPR1), peptidase inhibitor 15 (PI15), peptidase inhibitor 16 (PI16), CRISP LCCL domain containing 1 and 2 (CRISPLD1/CAPLD1 and CRISPLD2/CAPLD2), mannose receptor-like/CP domain, CTL domain containing (CAPCL) and the R3H domain-like protein (R3HMDL). CRISP (cysteine rich secretory proteins) proteins (venom-related proteins, and proteins produced by reproductive organs and cells) and plant-derived pathogenesis related proteins are the best characterized. Helminth parasite proteins of this superfamily were first reported in hookworms and later in related nematodes and platyhelminths. While nematodes' CAP proteins are known as Ancylostoma secreted proteins (ASPs), platyhelminths' CAP are known as venom allergen-like (VAL) proteins. Some of these proteins have been studied as vaccine candidates due to their immunogenic and protective properties (e.g. Na-ASP-2, Ov-Asp1, Oo-ASP-1) [1].

This clan contains 2 families and the total number of domains in the clan is 28430. The clan was built by S El-Gebali.

Literature references

  1. Silvarrey MC, Echeverria S, Costabile A, Castillo E, Paulino M, Esteves A;, Acta Trop. 2016;158:59-67.: Identification of novel CAP superfamily protein members of Echinococcus granulosus protoscoleces. PUBMED:26899679 EPMC:26899679


This clan contains the following 2 member families:


Domain organisation

Below is a listing of the unique domain organisations or architectures from this clan. More...

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The table below shows the number of occurrences of each domain throughout the sequence database. More...

Pfam family Num. domains Alignment
CAP (PF00188) 28061 (98.7%) View
ASPRs (PF17641) 369 (1.3%) View
Total: 2 Total: 28430 Clan alignment

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Family relationships

This diagram shows the relationships between members of this clan. More...

Species distribution

Tree controls


This tree shows the occurrence of the domains in this clan across different species. More...



For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt three-dimensional structures. The table below shows the mapping between the Pfam families in this clan, the corresponding UniProt entries, and the region of the three-dimensional structures that are available for that sequence.

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