title: A flexible, multilayered protein scaffold maintains the slit in between glomerular podocytes.
abstract: Vertebrate life critically depends on renal filtration and excretion of low molecular weight waste products. This process is controlled by a specialized cell-cell contact between podocyte foot processes: the slit diaphragm (SD). Using a comprehensive set of targeted KO mice of key SD molecules, we provided genetic, functional, and high-resolution ultrastructural data highlighting a concept of a flexible, dynamic, and multilayered architecture of the SD. Our data indicate that the mammalian SD is composed of NEPHRIN and NEPH1 molecules, while NEPH2 and NEPH3 do not participate in podocyte intercellular junction formation. Unexpectedly, homo- and heteromeric NEPHRIN/NEPH1 complexes are rarely observed. Instead, single NEPH1 molecules appear to form the lower part of the junction close to the glomerular basement membrane with a width of 23 nm, while single NEPHRIN molecules form an adjacent junction more apically with a width of 45 nm. In both cases, the molecules are quasiperiodically spaced 7 nm apart. These structural findings, in combination with the flexibility inherent to the repetitive Ig folds of NEPHRIN and NEPH1, indicate that the SD likely represents a highly dynamic cell-cell contact that forms an adjustable, nonclogging barrier within the renal filtration apparatus.
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Grahammer
authors.affiliation: Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wigge
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.|Spemann Graduate School of Biology and Medicine.|Faculty of Biology, and.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schell
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.|BIOSS Center for Biological Signalling Studies, Albert-Ludwigs University of Freiburg, Freiburg, Germany.|Institute of Anatomy, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kretz
authors.affiliation: KI/AZ Integrated Cardio-Metabolic Center (ICMC), Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Patrakka
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Schneider
authors.affiliation: Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.|German Cancer Consortium and.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Klose
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Kind
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.|BIOSS Center for Biological Signalling Studies, Albert-Ludwigs University of Freiburg, Freiburg, Germany.|Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Sebastian J
authors.initials: SJ
authors.lastname: Arnold
authors.affiliation: Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Habermann
authors.affiliation: Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany.
authors.forename: Ricarda
authors.initials: R
authors.lastname: Bräuniger
authors.affiliation: Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
authors.forename: Markus M
authors.initials: MM
authors.lastname: Rinschen
authors.affiliation: Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
authors.forename: Linus
authors.initials: L
authors.lastname: Völker
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bregenzer
authors.affiliation: Institute of Virology, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Rubbenstroth
authors.affiliation: Institute of Molecular Medicine and Cell Research, Faculty of Medicine, University of Freiburg, Freiburg, Germany.|German Cancer Consortium and.|German Cancer Research Center, Heidelberg, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Boerries
authors.affiliation: Department of Pathology, University of Vienna, Vienna, Austria.
authors.forename: Dontscho
authors.initials: D
authors.lastname: Kerjaschki
authors.affiliation: Renal Division, Washington University, St. Louis, Missouri, USA.
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Miner
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
authors.forename: Gerd
authors.initials: G
authors.lastname: Walz
authors.affiliation: Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Benzing
authors.affiliation: Division of Nephrology and Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, Florida, USA.
authors.forename: Alessia
authors.initials: A
authors.lastname: Fornoni
authors.affiliation: Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Frankfurt, Germany.
authors.forename: Achilleas S
authors.initials: AS
authors.lastname: Frangakis
authors.affiliation: Department of Medicine, Division of Nephrology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.|Spemann Graduate School of Biology and Medicine.|BIOSS Center for Biological Signalling Studies, Albert-Ludwigs University of Freiburg, Freiburg, Germany.|FRIAS, Freiburg Institute for Advanced Studies and ZBSA, Center for Biological System Analysis, Albert-Ludwigs-University of Freiburg, Germany.
authors.forename: Tobias B
authors.initials: TB
authors.lastname: Huber