Gene Ontology annotation through association of InterPro records with GO terms

Annotation inferences using phylogenetic trees

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

GO_REF:0000117

Electronic Gene Ontology annotations created by ARBA machine learning models

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

PMID:22522420

ISPD loss-of-function mutations disrupt dystroglycan O-mannosylation and cause Walker-Warburg syndrome.

Wild-type CRPPA rescues functional alpha-dystroglycan glycosylation in patient fibroblasts; the tested patient exon-3-deletion construct does not.

PMID:22522421

Mutations in ISPD cause Walker-Warburg syndrome and defective glycosylation of α-dystroglycan.

Human recessive variants and zebrafish splice-blocking perturbations support CRPPA involvement in alpha-dystroglycan glycosylation; muscle degeneration is a consequence, not a separate autonomous molecular activity.

PMID:26687144

Human ISPD Is a Cytidyltransferase Required for Dystroglycan O-Mannosylation.

Human CRPPA synthesizes pentose-phosphate CDP products, including chemically characterized CDP-ribitol; the tagged full-length protein localizes to cytosol.
The human 43–451 crystal forms a dimer; consistent solution gel filtration is reported without shown data.
Two independently generated HAP1 knockout clones have defective glycosylation with unchanged measured dolichol species and levels; basal MEP turnover in vitro does not establish an operating human MEP pathway.

PMID:26923585

Identification of a Post-translational Modification with Ribitol-Phosphate and Its Defect in Muscular Dystrophy.

Human CRPPA synthesizes CDP-ribitol; separate FKTN and FKRP reactions transfer ribitol phosphate sequentially to the glycan.

PMID:27130732

The functional O-mannose glycan on α-dystroglycan contains a phospho-ribitol primed for matriglycan addition.

Purified human 43–451 CRPPA generates CDP-ribitol and CDP-ribose from their phosphorylated acceptors and CTP; free sugars do not substitute in the tested assay.

Reactome:R-HSA-9940844

CRPPA dimer transfers cytidylyl to Rbt5P

The cytosolic CRPPA homodimer is modeled as the catalyst that produces CDP-ribitol, with two components resolving to human A4D126.

PMID:27194101

ISPD produces CDP-ribitol used by FKTN and FKRP to transfer ribitol phosphate onto α-dystroglycan.

Recombinant mouse Ispd, human knockout/rescue and rat-muscle metabolite experiments support CDP-ribitol donor production; bacterial TarI rescue separates donor synthesis from a necessary additional mammalian catalytic activity.

file:human/CRPPA/CRPPA-uniprot.txt

UniProtKB A4D126 CRPPA protein record