FKRP

FKRP encodes glycosyltransferase-like protein and is considered as a causative gene of limb-girdle muscular dystrophy. FKRP has homology to glycosyltransferase-like protein Fukutin (considered as a causative gene of Fukuyama congenital muscular dystrophy), and thus named as fukutin-related protein (FKRP). The gene-knockout mice exhibit glycan structure alteration of α−dystroglycan. FKRP synthesizes the Rbo5P structure (Rbo5P-Rbo5P-3GalNAcb1-3GlcNAcb1-4(phospho-6)Man-Ser/Thr), the second of the tandem repeats of ribitol 5-phosphate (Rbo5P) in the O-mannose glycan structure of α−dystroglycan. The substrate sugar nucleotide, cytidine diphosphate ribitol (CDP-Rbo) is synthesized by isoprenoid synthase domain-containing protein (ISPD), which is also known as a causative gene of muscular dystrophy.