About SNX / Sorting Nexin:
Sorting nexins (commonly shortened to SNX) are proteins. This is a large group, which you’ll find in the cytoplasm. They are able to associate with membranes because of their lipid-binding PX domain (this is a phospholipid-binding motif), or they can do it through protein-protein interactions, if it’s related to membrane-associated protein complexes. While the research has been limited, researchers have found that there are some members of the family that can facilitate protein sorting.
SNX Structure
In terms of structure, SNX consists of a PX domain or they’ll have a structure that consists of the PX as well as additional domains. There’s a subgroup of SNX that you’ll find in humans -- these run from SNX1 through to SNX9, and then SNX18, SNX30, SNX32, and SNX33 -- and these contain a BAR domain that you’ll find at their C-terminus. In terms of homology, they’re close to several yeast proteins, such as Vps5p and Mvp1p.
Sorting Nexin Mechanism
Some of the SNX family have been shown to bind to multiple receptor tyrosine kinases -- the research shows that receptors for epidermal growth factor, platelet-derived growth factor, and also insulin. The most novel member of the sorting nexins family is SNX6, which researchers have observed will interact with members of the transforming growth factor-beta family of receptor threonine kinases. Researchers have also observed strong heteromeric interactions among SNX1, -2, -4, and -6. This indicates a possibility that there’s a formation in the vivo of oligomeric complexes. This indicates that there may be a relationship between SNX and the receptor serine-threonine kinases.