Nephrin-associated phospho-protein network necessary for filtration at the slit-diaphragm and podocyte adhesion

Minimal change disease (MCD) is characterized by nephrotic syndrome. In a subgroup of patients, pathogenic antibodies against the slit-diaphragm protein Nephrin encoded by the gene NPHS1 were identified in blood and biopsy samples. We employed a model of MCD with antibody-mediated clustering of Nephrin, leading to tyrosine-dependent signal transduction in podocyte cell culture. Phospho-proteome analysis revealed approx. 180 differentially phosphorylated peptides. Among them, we identified Rapgef1 as differentially phsophorylated following Nephrin activation. Therefore, we aimed to study the role of Rapgef1 in mice glomeruli, by isolating glomeruli either from Rapgef1 flox/flox x Six2 Cre -/- (control) or Rapgef1 flox/flox x Six2 Cre +/- (knockout) mice.

微小病变性肾病（Minimal change disease, MCD）以肾病综合征为特征。在部分患者亚组中，研究人员于血液及活检样本中检出了针对由基因NPHS1编码的裂孔膜蛋白nephrin（Nephrin）的致病性抗体。本研究采用了抗体介导nephrin聚集的MCD模型，该模型可在足细胞细胞培养中引发酪氨酸依赖性信号转导。磷酸化蛋白质组学分析共鉴定出约180个差异磷酸化肽段。其中，我们发现Rapgef1在nephrin激活后呈现出差异磷酸化状态。因此，本研究旨在通过分离Rapgef1 flox/flox × Six2 Cre -/-（对照组）或Rapgef1 flox/flox × Six2 Cre +/-（敲除组）小鼠的肾小球，探究Rapgef1在小鼠肾小球中的作用。