COS domain (IPR017903)

Short name: COS_domain

Overlapping homologous superfamilies


Domain relationships



N-terminal RING finger/B-box/coiled coil (RBCC) or tripartite motif (TRIM) proteins, which are found in metazoa, are involved in a vast array of intracellular functions. They appear to function as part of large protein complexes and possess ubiquitin-protein isopeptide ligase activity. The following RBCC proteins contain an ~60-residue COS (C-terminal subgroup one signature) domain, which is also found in a distantly related non-RBCC microtubule-binding protein, GLFND:

  • Vertebrate MID1 and MID2, which associate with microtubules through homo- and heterodimerization
  • Animal TRIM9, which plays a regulatory role in synaptic vesicle exocytosis
  • Mammalian TRIM nine-like (TNL)
  • Mammalian TRIM36, which could play a regulatory role in exocytosis of the sperm vesicle
  • Mammalian tripartite, fibronectin type III and C-terminal B30.2/SPRY (TRIFIC)
  • Mammalian muscle-specific RING finger (MURF) family. MURF proteins have an ability to form both homo- and heterodimers with each other and to associate with the microtubule cytoskeleton
In addition to RBCC, the COS domain is also found in association with B30.2/SPRY or fibronectin type-III (FN3) domains.

The COS domain is predicted to consist of two alpha-helical coils [PMID: 16434393].

Contributing signatures

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