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c-mip impairs podocyte proximal signaling and induces heavy proteinuria.
- Source :
-
Science signaling [Sci Signal] 2010 May 18; Vol. 3 (122), pp. ra39. Date of Electronic Publication: 2010 May 18. - Publication Year :
- 2010
-
Abstract
- Idiopathic nephrotic syndrome comprises several podocyte diseases of unknown origin that affect the glomerular podocyte, which controls the permeability of the filtration barrier in the kidney to proteins. It is characterized by the daily loss of more than 3 g of protein in urine and the lack of inflammatory lesions or cell infiltration. We found that the abundance of c-mip (c-maf inducing protein) was increased in the podocytes of patients with various acquired idiopathic nephrotic syndromes in which the podocyte is the main target of injury. Mice engineered to have excessive c-mip in podocytes developed proteinuria without morphological alterations, inflammatory lesions, or cell infiltration. Excessive c-mip blocked podocyte signaling by preventing the interaction of the slit diaphragm transmembrane protein nephrin with the tyrosine kinase Fyn, thereby decreasing phosphorylation of nephrin in vitro and in vivo. Moreover, c-mip inhibited interactions between Fyn and the cytoskeletal regulator N-WASP (neural Wiskott-Aldrich syndrome protein) and between the adaptor protein Nck and nephrin, potentially accounting for cytoskeletal disorganization and the effacement of foot processes seen in idiopathic nephrotic syndromes. The intravenous injection of small interfering RNA targeting c-mip prevented lipopolysaccharide-induced proteinuria in mice. Together, these results identify c-mip as a key component in the molecular pathogenesis of acquired podocyte diseases.
- Subjects :
- Adaptor Proteins, Signal Transducing
Animals
Carrier Proteins biosynthesis
Carrier Proteins genetics
Humans
Membrane Proteins metabolism
Mice
Mice, Transgenic
Phosphorylation
Podocytes metabolism
Protein Binding
Proto-Oncogene Proteins c-fyn metabolism
RNA Interference
Wiskott-Aldrich Syndrome Protein, Neuronal metabolism
Carrier Proteins physiology
Podocytes physiology
Proteinuria physiopathology
Signal Transduction physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1937-9145
- Volume :
- 3
- Issue :
- 122
- Database :
- MEDLINE
- Journal :
- Science signaling
- Publication Type :
- Academic Journal
- Accession number :
- 20484117
- Full Text :
- https://doi.org/10.1126/scisignal.2000678