The TRIM37 gene encodes a peroxisomal RING-B-box-coiled-coil protein: classification of mulibrey nanism as a new peroxisomal disorder.
Mulibrey nanism is a rare growth disorder of prenatal onset caused by mutations in the TRIM37 gene, which encodes a RING-B-box-coiled-coil protein. The pathogenetic mechanisms of mulibrey nanism are unknown. We have used transiently transfected cells and antibodies raised against the predicted TRIM37 protein to characterize the TRIM37 gene product and to determine its intracellular localization. We show that the human TRIM37 cDNA encodes a peroxisomal protein with an apparent molecular weight of 130 kD. Peroxisomal localization is compromised in mutant protein representing the major Finnish TRIM37 mutation but is retained in the protein representing the minor Finnish mutation. Colocalization of endogenous TRIM37 with peroxisomal markers was observed by double immunofluorescence staining in HepG2 and human intestinal smooth muscle cell lines. In human tissue sections, TRIM37 shows a granular cytoplasmic pattern. Endogenous TRIM37 is not imported into peroxisomes in peroxin 1 (PEX1(-/-)) and peroxin 5 (PEX5(-/-)) mutant fibroblasts but is imported normally in peroxin 7 (PEX7(-/-)) deficient fibroblasts, giving further evidence for a peroxisomal localization of TRIM37. Fibroblasts derived from patients with mulibrey nanism lack C-terminal TRIM37 immunoreactivity but stain normally for both peroxisomal matrix and membrane markers, suggesting apparently normal peroxisome biogenesis in patient fibroblasts. Taken together, this molecular evidence unequivocally indicates that TRIM37 is located in the peroxisomes, and Mulibrey nanism thus can be classified as a new peroxisomal disorder.
Kallijärvi
Jukka
J
Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, Biomedicum Helsinki, Finland.
Avela
Kristiina
K
Lipsanen-Nyman
Marita
M
Ulmanen
Ismo
I
Lehesjoki
Anna-Elina
AE
D000074183:ATPases Associated with Diverse Cellular Activities; D020816:Amino Acid Motifs; D000818:Animals; D000906:Antibodies / Q000276:immunology; D015153:Blotting, Western; D002460:Cell Line; D006224:Cricetinae; D004392:Dwarfism / Q000235:genetics* / Q000378:metabolism; D005347:Fibroblasts; D005387:Finland; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins; D018901:Peroxisomal Disorders / Q000235:genetics* / Q000378:metabolism; D000074437:Peroxisomal Targeting Signal 2 Receptor; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry* / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases
D000906:Antibodies; D006023:Glycoproteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; C000614264:PEX5 protein, human; C000614269:PEX7 protein, human; D000074437:Peroxisomal Targeting Signal 2 Receptor; D000074435:Peroxisome-Targeting Signal 1 Receptor; D011506:Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D000070584:Tripartite Motif Proteins; C411745:TRIM37 protein, human; D044767:Ubiquitin-Protein Ligases; D000074183:ATPases Associated with Diverse Cellular Activities; C111808:PEX1 protein, human