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Updated: Aug 30, 2026
Comparative Strategies for Ubiquitination Detection in Mammalian Cell Lysates Using SMAD2/SMURF2 as a Model
Published on: April 17, 2026
The ubiquitously expressed MURR1 protein is absent in canine copper toxicosis
Adriana E M Klomp1, Bart van de Sluis, Leo W J Klomp
1Department of Metabolic and Endocrinic Diseases, University Medical Center Utrecht, room KC02.069.1, Utrecht University, Lundlaan 6, 3584 EA Utrecht, The Netherlands.
Background/Aims:
Copper toxicosis (CT) in Bedlington terriers is an autosomal recessive disorder characterized by massive lysosomal copper accumulation in livers of affected dogs, and a defect in the biliary excretion of this metal. We propose that MURR1, the gene defective in canine CT, has a role in the regulation of copper excretion into bile during copper overload.
Methods:
Polyclonal antibodies raised against full-length recombinant human MURR1 were used for immunoblot analysis and indirect immunofluorescence studies.
Results:
Using Western blot analysis, these antibodies abundantly detected MURR1 as a 23 kDa protein in liver extracts of mice and dogs, but MURR1 was undetectable in the livers of affected Bedlington terriers. MURR1 was also detected in different tissues and cell lines; in cell lines the protein was found both in cytosol and membrane preparations. Consistent with this observation, indirect immunofluorescence staining revealed that in some cells MURR1 was associated with a vesicular compartment diffusely localized throughout the cell.
Conclusions:
The genomic deletion in MURR1 results in complete absence of MURR1 protein. Based on the unanticipated subcellular localization, our results suggest a role for MURR1 in the regulation of vesicular copper sequestration during copper overload.
