X8 protein domain explained

Symbol:	X8
X8
Pfam:	PF07983
Interpro:	IPR012946
Scop:	1occ

In molecular biology, the X8 domain, is thought to play a role in targeting the plasmodesmata by providing it with structural support. The domain is able to do this since it contains signal sequences for a glycosylphosphatidylinositol (GPI) linkage to the extracellular face of the plasma membrane. This domain is involved in carbohydrate binding.^[1]

Structure

The X8 domain^[2] contains 6 conserved cysteine residues that presumably form three disulphide bridges. The domain is also found in an Olive pollen allergen^[3] as well as at the C terminus of family 17 glycosyl hydrolases.^[4]

Notes and References

1. Simpson C, Thomas C, Findlay K, Bayer E, Maule AJ . An Arabidopsis GPI-anchor plasmodesmal neck protein with callose binding activity and potential to regulate cell-to-cell trafficking. . Plant Cell . 2009 . 21 . 2 . 581–94 . 19223515 . 10.1105/tpc.108.060145 . 2660613 .
2. Henrissat B, Davies GJ . Glycoside hydrolases and glycosyltransferases. Families, modules, and implications for genomics . Plant Physiol. . 124 . 4 . 1515–9 . December 2000 . 11115868 . 1539306 . 10.1104/pp.124.4.1515.
3. Barral P, Batanero E, Palomares O, Quiralte J, Villalba M, RodrÃguez R . A major allergen from pollen defines a novel family of plant proteins and shows intra- and interspecies [correction of interspecie] cross-reactivity . J. Immunol. . 172 . 6 . 3644–51 . March 2004 . 15004167 . 10.4049/jimmunol.172.6.3644. free .
4. Henrissat B, Coutinho PM, Davies GJ . A census of carbohydrate-active enzymes in the genome of Arabidopsis thaliana . Plant Mol. Biol. . 47 . 1–2 . 55–72 . September 2001 . 11554480 . 10.1007/978-94-010-0668-2_4. 978-94-010-3861-4 .