Sorting nexin

PX domain
Structure of the PX domain from p40(phox) bound to phosphatidylinositol 3-phosphate.[1]
Identifiers
Symbol	PX
Pfam	PF00787
InterPro	IPR001683
SMART	PX
PROSITE	PDOC50195
SCOP	1h6h
SUPERFAMILY	1h6h
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Sorting nexin, N-terminal domain
Identifiers
Symbol	Sorting_nexin
Pfam	PF03700
InterPro	IPR005329
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Vps5 C terminal like (BAR domain)
Identifiers
Symbol	Vps5
Pfam	PF09325
InterPro	IPR015404
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Sorting nexin, C terminal domain
Identifiers
Symbol	Nexin_C
Pfam	PF08628
InterPro	IPR013937
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

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^[2][3] 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
	N-terminus	Mid-1	Mid-2	Mid-3	C-terminus
SNX1, SNX2	Sorting_nexin_N	–	PX	–	BAR[4] (Vps5)
SNX4, SNX7, SNX8, SNX30	–	–	PX	–	BAR[4] (Vsp5)
SNX5, SNX6, SNX32	–	–	PX	–	BAR[4]
SNX9, SNX18, SNX33	SH3	–	PX	–	BAR[4] (BAR_3_WASP_bdg)[5]
SNX13, SNX14, SNX19, SNX25	PXA[6]	RGS	PX	–	Nexin_C
SNX15	–	–	PX	–	MIT[7]
SNX17, SNX31	–	–	PX	RA[8]	FERM_M[9]
SNX23	kinesin_motor	SMAD_FHA[10]	PX	–	–
SNX26	–	–	PX	SH3	RhoGAP
SNX27	PDZ	–	PX	-	RA
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:

1. NTD – N-terminal domain
2. PX domain
3. CTD – C-terminal BAR domain

Schematic diagram of the 1D structures of a representative sorting nexin, the sorting nexin 1 (SNX1). NTD = N-terminal SNX domain, PX = PX domain, CTD = C-terminal BAR domain.

References

1. Bravo J, Karathanassis D, Pacold CM, et al. (October 2001). "The crystal structure of the PX domain from p40(phox) bound to phosphatidylinositol 3-phosphate". Mol. Cell. 8 (4): 829–39. doi:10.1016/S1097-2765(01)00372-0. PMID 11684018.
2. Dixon JE, Worby CA (2002). "Sorting out the cellular functions of sorting nexins". Nat. Rev. Mol. Cell Biol. 3 (12): 919–931. doi:10.1038/nrm974. PMID 12461558.
3. Worby CA, Dixon JE (2002). "Sorting out the cellular functions of sorting nexins". Nat. Rev. Mol. Cell Biol. 3 (12): 919–31. doi:10.1038/nrm974. PMID 12461558.
4. Frost A, Unger VM, De Camilli P (April 2009). "The BAR domain superfamily: membrane-molding macromolecules". Cell. 137 (2): 191–196. doi:10.1016/j.cell.2009.04.010. PMID 19379681.
5. BAR_3_WASP_bdg: WASP-binding domain of Sorting nexin protein, Pfam PF10456
6. PXA: PXA domain, Pfam PF02194
7. MIT: MIT (microtubule interacting and transport) domain, Pfam PF04212
8. RA: Ras association (RalGDS/AF-6) domain, Pfam PF00788
9. FERM_M: FERM central domain, Pfam PF00373
10. SMAD_FHA: SMAD/FHA domain, InterPro: IPR008984

External links

• Sorting Nexins at the US National Library of Medicine Medical Subject Headings (MeSH)