Ribitol-5-phosphate transferase FKTN is a eukaryotic protein necessary for the maintenance of muscle integrity, cortical histiogenesis, and normal ocular development. Mutations in the fukutin gene have been shown to result in Fukuyama-type congenital muscular dystrophy characterised by brain malformation - one of the most common autosomal-recessive disorders in Japan []. FKTN participates in glycosylation of alpha-dystroglycan/DAG1 [, , ].This entry also include the Protein MNN4 from budding yeast. It may function as a positive regulator for mannosylphosphate transferase [, ].
This is the N-terminal domain of Ribitol-5-phosphate transferase FKTN (also referred to fukutin) which contains the transmembrane domain required for its localisation to the Golgi and participates in the interaction with POMGnT1 (Protein O-linked-mannose beta-1,2-N-acetylglucosaminyltransferase 1) for normal POMGnT1 location and activity []. FKTN is a ribitol-phosphate transferase that forms a complex with FKRP (fukutin-related protein, also a ribitol-phosphate transferase) and TMEM5 (a ribitol xylosyltransferase). Fukutin, FKRP, and TMEM5 maintain each of their enzyme activities in the complex and may contribute to specificbiosynthesis of glycans required for dystroglycan function [].
The LicD family of proteins show high sequence similarity and are involved in phosphorylcholine metabolism. There is evidence to show that LicD2 mutants have a reduced ability to take up choline, have decreased ability to adhere to host cells and are less virulent []. These proteins are part of the nucleotidyltransferase superfamily [].Ribitol-5-phosphate transferase FKTN (also known as Fukutin), which is a member of the LicD family, is a mammal protein which may be involved in the modification of glycan moieties of alpha-dystroglycan; defects in Fukutin are associated with congential muscular dystrophy [, ]. Ribitol 5-phosphate transferase FKRP (also known as Fukutin-related protein), responsible for the the second step in the formation of the ribose 5-phosphate tandem repeat after FKTN activity [, ], has N-terminal stem and C-terminal catalytic domains, and adopts a tetramer assembly [].