title: Pathogenic uromodulin mutations result in premature intracellular polymerization.
abstract: Several renal diseases involve mutations in the gene encoding uromodulin, the predominant protein in urine. We investigated the intracellular processing of wild-type uromodulin, and three mutants: p.V93_G97del/ins AASC; C155R; and C150S. A renal biopsy from a patient harboring the C155R mutation revealed intracellular protein accumulation. Wild-type uromodulin was efficiently trafficked to the cell surface in transfected tsA 201 cells, whereas the mutants were partially retained within the cell, and incompletely processed. Atomic force microscopy imaging revealed that the intracellular mutant proteins contained fibrillar structures similar to urinary uromodulin. We suggest that premature intracellular polymerization underlies the pathology of uromodulin diseases.
authors.affiliation: Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom. Electronic address: aps54@cam.ac.uk.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Stewart
authors.affiliation: Department of Medical Genetics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Richard N
authors.initials: RN
authors.lastname: Sandford
authors.affiliation: Department of Medical Genetics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Fiona E
authors.initials: FE
authors.lastname: Karet Frankl
authors.affiliation: Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Edwardson
mesh_terms: D019943:Amino Acid Substitution; D005260:Female; D030342:Genetic Diseases, Inborn / Q000235:genetics / Q000473:pathology / Q000652:urine*; D057809:HEK293 Cells; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics / Q000473:pathology / Q000652:urine*; D008297:Male; D020125:Mutation, Missense; D066263:Protein Aggregation, Pathological / Q000235:genetics / Q000473:pathology / Q000652:urine*; D021381:Protein Transport / Q000235:genetics; D058949:Uromodulin / Q000235:genetics / Q000652:urine*
chemical_list: C548612:UMOD protein, human; D058949:Uromodulin
keywords: Atomic force microscopy; Nephropathy; Protein polymerization; Uromodulin