Type II secretion system protein C (IPR001639)

Short name: T2SS_protein-C

Overlapping homologous superfamilies


Family relationships



The general (type II) secretion pathway (GSP) within Gram-negative bacteria is a signal sequence-dependent process responsible for protein export [PMID: 8438237, PMID: 1365398, PMID: 1592799]. The process has two stages: exoproteins are first translocated across the inner membrane by the general signal-dependent export pathway (GEP), and then across the outer membrane by a species-specific accessory mechanism.

A number of molecules are involved in the GSP; one of these is known as the 'C' protein, the most probable location of which is the inner membrane [PMID: 2677007]. This suggests that protein C is part of the GEP apparatus, aiding trans-location of exoproteins from the cytoplasm to the periplasm, prior to transport across the outer membrane. The size of the 'C' protein is around 270 to 300 amino acids. It apparently contains a single transmembrane domain located in the N-terminal section. The short N-terminal domain is predicted to be cytoplasmic and the large C-terminal domain periplasmic.

The gene encoding the 'C' protein has been sequenced in a variety of bacteria such as Aeromonas (exeC); Erwinia (outC); Escherichia coli (yheE or gspC); Klebsiella pneumoniae (pulC); or Vibrio cholerae (epsC).

GO terms

Biological Process

GO:0015628 protein secretion by the type II secretion system

Molecular Function

GO:0008565 protein transporter activity

Cellular Component

GO:0015627 type II protein secretion system complex

Contributing signatures

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