About SPSB / SPRY Domain-Containing SOCS Cox:
The SPSB is a substrate recognition component of a SCF-like ECS (which stands for Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin=protein ligase complex.
SPSB Function
This functions to mediate the ubiquitination and subsequent proteasomal degradation of target proteins. Studies have also shown that it will negatively regulate nitric oxide production, and also that it functions to limit cellular toxicity in activated macrophages.
SPRY Domain-Containing SOCS Cox Mechanism
It does this by mediating the ubiquitination and proteasomal degradation of NOS2. It can also act as a bridge, which helps to link NOS2 with the ECS E3 ubiquitin ligase complex components ELOC and CUL5. Researchers have also found that the protein can play a role in the pathway protein ubiquitination, which forms part of the protein modification. It has been shown to be essential for cell viability.
SPSB Activity
In terms of catalytic activity, there is cleavage of hydrophobic, n-terminal signal or leader sequences, which come from the secreted and periplasmic proteins.
SPRY Domain-Containing SOCS Cox Structure
In terms of structure, the SPSB is a component of the probable ECS E3 ubiquitin -protein ligase complex, which contains CUL5, RNF7/RBX2, elongin BC complex, and SPSB1.
SPSB Interactions
It has been shown to interact with ELOC, ELOB, RNF7, and CUL5. Researchers have observed that it interacts in a direct way with the MET tyrosine kinase domain, both in the presence of HGF as well as the absence of HGF. HGF treatments have been shown to have a positive impact on the interaction. It also interacts with PAWR -- this interaction occurs in association with the Elongin BC complex. Also interacts with NOS2.