The chlamydial inclusion membrane is extensively modified by the insertion of type III secreted effector proteins. These inclusion membrane proteins (Incs) are exposed to the cytosol and share a common structural feature of a long, bi-lobed hydrophobic domain but little or no primary amino acid sequence similarity [1]. This family has members such as the IncF proteins found in Chlamydia trachomatis. IncF, is enriched at the point of contact of RBs (reticulate bodies) with the inclusion membrane [1]. It is expressed early in the developmental cycle and interacts with many other Inc proteins, like Ct058 or Ct850, which are expressed later during the cycle. Thus, IncF could act as an interaction node for Inc proteins. IncF consists of 104 amino acids of which 38 N-terminal amino acids encoding the signal sequence for the type III system and 12 C-terminal amino acids may be localized in the host cell cytoplasm. Suggesting that IncF or other small Incs interact with other Inc proteins by their trans-membrane domain. It has been identified to be capable of homo-oligomerization and also displayed self-interacting properties [2].

1: Role for chlamydial inclusion membrane proteins in inclusion membrane structure and biogenesis. Mital J, Miller NJ, Dorward DW, Dooley CA, Hackstadt T; PLoS One. 2013;8:e63426. PMID:23696825

2: Characterization of interactions between inclusion membrane proteins from Chlamydia trachomatis. Gauliard E, Ouellette SP, Rueden KJ, Ladant D; Front Cell Infect Microbiol. 2015;5:13. PMID:25717440