8,A.229.  The Chlamydial Inclusion Membrane Protein, MrcA (MrcA) Family 

The obligate intracellular bacterium, Chlamydia trachomatis, replicates within a parasitophorous vacuole termed an inclusion. During development, host proteins critical for regulating intracellular calcium (Ca2+) homeostasis interact with the inclusion membrane. The inclusion membrane protein, MrcA, interacts with the inositol-trisphosphate receptor (IP3R), an ER cationic channel that conducts Ca2+. Stromal interaction molecule 1 (STIM1), an ER transmembrane protein important for regulating store-operated Ca2+ entry (SOCE), localizes to the inclusion membrane via an uncharacterized interaction. Chamberlain et al. 2022 examined Ca2+ mobilization in C. trachomatis infected cells. Utilizing a variety of Ca2+ indicators to assess changes in cytosolic Ca2+ concentration, they demonstrate that C. trachomatis impairs host cell SOCE. Ca2+ regulates many cellular signaling pathways. The SOCE-dependent NFAT/calcineurin signaling pathway is impaired in C. trachomatis infected HeLa cells and likely has major implications on host cell physiology as it relates to C. trachomatis pathogenesis.


 

References:

Chamberlain, N.B., Z. Dimond, and T. Hackstadt. (2022). Chlamydia trachomatis suppresses host cell store-operated Ca entry and inhibits NFAT/calcineurin signaling. Sci Rep 12: 21406.

Examples:

TC#NameOrganismal TypeExample
8.A.229.1.1

Penicillin binding protein, MrcA of 428 aas and 1 - 3 TMSs.  This inclusion membrane protein interacts with the inositol trisphosphate receptor (IP3R) (TC# 1.A.3.2.6) influencing Ca2+ fluxes between the ER and the cytoplasm (Chamberlain et al. 2022).

MrcA of Chlamydia trachomatis

 
8.A.229.1.2

Membrane peptidoglycan carboxypeptidase of 847 aas and 1 N-terminal TMS.

PCP of Streptomyces avidinii