CpnT - Outer Membrane Channel Protein CpnT
These proteins form transmembrane pores that usually allow the energy independent passage of solutes across a membrane. The transmembrane portions of these proteins consist of β-strands which form a β-barrel. These porin-type proteins are found in the outer membranes of Gram-negative bacteria, mitochondria, plastids and possibly acid-fast Gram-positive bacteria.
95 subfamilies has been described by the Transporter Classification Database (TCDB).
CpnT Background Information
The outer membrane protein cpnT is expressed by the Mycobactera as Mycobacterium tuberculosis or Mycobacterium bovis. CpnT has a dual function in uptake of nutrients and induction of host cell death: After cleavage of the C-terminal region (TNT), the remaining protein (NTD) forms a pore assembled as Oligomer in the bacterial membrane.
UniProt: O05442 (Mycobacterium tuberculosis); UniProt: A0A0H3MAA9 (Mycobacterium bovis)
Topology and Function:
cpnT (Mycobacterium tuberculosis) has a dual function in uptake of nutrients and induction of host cell death. The N-terminal domain (NTD) forms an outer membrane channel and is used for uptake of nutrients across the outer membrane. The cleaved and secreted C-terminal toxic domain (TNT) acts as a glycohydrolase, which hydrolyzes the essential cellular coenzyme NAD+ in the cytosol of infected macrophages, leading to necrotic host cell death. TNT is Secreted into the cytosol of infected macrophages while the bacteria are still confined to the phagosome. Both functions are required for survival, replication and cytotoxicity of M.tuberculosis in macrophages.
& Bilayer recordings on Port-a-Patch and Orbit mini
Reviews and Links
Transporter classification database:
- Outer membrane channel protein CpnT (cpnT, Mycobacterium tuberculosis)
- Outer membrane channel protein CpnT (cpnT, Mycobacterium bovis)