Role of dynamin, synaptojanin, and endophilin in podocyte foot processes

• Published in: The Journal of clinical investigation Vol. 122; no. 12; pp. 4401 - 4411
• Main Authors: Soda, Keita, Balkin, Daniel M, Ferguson, Shawn M, Paradise, Summer, Milosevic, Ira, Giovedi, Silvia, Volpicelli-Daley, Laura, Tian, Xuefei, Wu, Yumei, Ma, Hong, Son, Sung Hyun, Zheng, Rena, Moeckel, Gilbert, Cremona, Ottavio, Holzman, Lawrence B, De Camilli, Pietro, Ishibe, Shuta
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.12.2012
• Subjects: Actin; Actins - metabolism; Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Age; Animals; Biomedical research; Blood vessels; Cells, Cultured; Creatinine; Cytoskeleton; Development; Dynamin; Dynamin I - genetics; Dynamin I - metabolism; Dynamin II - genetics; Dynamin II - metabolism; Embryogenesis; Endocytosis; Epithelial cells; Filtration; Foot; Gene expression; Genetic aspects; Glomerular Filtration Barrier - metabolism; Glomerular Filtration Barrier - pathology; Kidney; Kidney diseases; Kidneys; Mice; Mice, Knockout; Microscopy, Confocal; Microscopy, Fluorescence; Nephrotic syndrome; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurons; Phosphoric Monoester Hydrolases - genetics; Phosphoric Monoester Hydrolases - metabolism; Podocytes - metabolism; Properties; Protein turnover; Proteins; Proteinuria; Proteinuria - genetics; Proteinuria - pathology; Renal Insufficiency - genetics; Renal Insufficiency - pathology; Renal Insufficiency - urine; Synaptic vesicles; Synaptogenesis; Urine; United States
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/jci65289

Podocytes are specialized cells that play an integral role in the renal glomerular filtration barrier via their foot processes. The foot processes form a highly organized structure, the disruption of which causes nephrotic syndrome. Interestingly, several similarities have been observed between mechanisms that govern podocyte organization and mechanisms that mediate neuronal synapse development. Dynamin, synaptojanin, and endophilin are functional partners in synaptic vesicle recycling via interconnected actions in clathrin-mediated endocytosis and actin dynamics in neurons. A role of dynamin in the maintenance of the kidney filtration barrier via an action on the actin cytoskeleton of podocytes was suggested. Here we used a conditional double-KO of dynamin 1 (Dnm1) and Dnm2 in mouse podocytes to confirm dynamin's role in podocyte foot process maintenance. In addition, we demonstrated that while synaptojanin 1 (Synj1) KO mice and endophilin 1 (Sh3gl2), endophilin 2 (Sh3gl1), and endophilin 3 (Sh3gl3) triple-KO mice had grossly normal embryonic development, these mutants failed to establish a normal filtration barrier and exhibited severe proteinuria due to abnormal podocyte foot process formation. These results strongly implicate a protein network that functions at the interface between endocytosis and actin at neuronal synapses in the formation and maintenance of the kidney glomerular filtration barrier.