COX4NB Protein, Human (His)

COX4NB protein serves as a crucial component of the endoplasmic reticulum membrane protein complex (EMC), facilitating the energy-independent insertion of newly synthesized membrane proteins into endoplasmic reticulum (ER) membranes. It exhibits a preference for accommodating proteins with transmembrane domains characterized by weak hydrophobicity or containing destabilizing features such as charged and aromatic residues. COX4NB is actively involved in both cotranslational and post-translational insertion processes, playing a key role in the cotranslational insertion of multi-pass membrane proteins where stop-transfer membrane-anchor sequences transform into ER membrane-spanning helices. Additionally, it is essential for the post-translational insertion of tail-anchored (TA) proteins into ER membranes. By mediating the proper cotranslational insertion of N-terminal transmembrane domains in an N-exo topology, positioning the translocated N-terminus in the ER lumen, COX4NB controls the topology of multi-pass membrane proteins, including G protein-coupled receptors. Indirectly influencing various cellular processes through its regulatory role in protein membrane insertion, COX4NB is a vital component of the EMC complex, where it functions in conjunction with other subunits like EMC8 and EMC9.