Sorting nexin
# Sorting nexin

Sorting nexins are a large group of proteins that are localized in the cytoplasm and have the potential for membrane association either through their lipid-binding PX domain (a phospholipid-binding motif) or through protein–protein interactions with membrane-associated protein complexes Some members of this family have been shown to facilitate protein sorting.

## Family members

In humans, sorting nexins are transcribed from the following genes:

| Genes | Domain Composition | Domain Composition | Domain Composition | Domain Composition | Domain Composition |
| - | - | - | - | - | - |
| Genes | N-terminus | Mid-1 | Mid-2 | Mid-3 | C-terminus |
| SNX1, SNX2 | Sorting_nexin_N | – | PX | – | BAR (Vps5) |
| SNX4, SNX7, SNX8, SNX30 | – | – | PX | – | BAR (Vsp5) |
| SNX5, SNX6, SNX32 | – | – | PX | – | BAR |
| SNX9, SNX18, SNX33 | SH3 | – | PX | – | BAR (BAR_3_WASP_bdg) |
| SNX13, SNX14, SNX19, SNX25 | PXA | RGS | PX | – | Nexin_C |
| SNX15 | – | – | PX | – | MIT |
| SNX17, SNX31 | – | – | PX | RA | FERM_M |
| SNX23 | kinesin_motor | SMAD_FHA | PX | – | – |
| SNX26 | – | – | PX | SH3 | RhoGAP |
| SNX27 | PDZ | – | PX | - | FERM_M |
| SNX28 | – | – | PX | SH3 | SH3 |
| SNX3, SNX10, SNX11, SNX12, SNX16, SNX20, SNX21, SNX22, SNX24, SNX29 | – | – | PX | – | – |

## Structure

Sorting nexins either consist solely of a PX domain (e.g. SNX3) or have a modular structure made up of the PX and additional domains.

A subgroup of sorting nexins (comprising, in humans, SNX1, SNX2, SNX4, SNX5, SNX6, SNX7, SNX8, SNX9, SNX18, SNX30, SNX32 and SNX33) possess a BAR domain at their C-terminus. (The BAR domain of SNXs 1, 2, 4, 7, 8 and 30 is classified by pfam as 'Vps5 C terminal like'.)

An example of a sorting nexin domain structure can be seen here for SNX1:

* NTD – N-terminal domain
* PX domain
* CTD – C-terminal BAR domain
