title: Microtubule Associated Protein 1b (MAP1B) Is a Marker of the Microtubular Cytoskeleton in Podocytes but Is Not Essential for the Function of the Kidney Filtration Barrier in Mice.
abstract: Podocytes are essential for the function of the kidney glomerular filter. A highly differentiated cytoskeleton is requisite for their integrity. Although much knowledge has been gained on the organization of cortical actin networks in podocyte's foot processes, less is known about the molecular organization of the microtubular cytoskeleton in primary processes and the cell body. To gain an insight into the organization of the microtubular cytoskeleton of the podocyte, we systematically analyzed the expression of microtubule associated proteins (Maps), a family of microtubules interacting proteins with known functions as regulator, scaffold and guidance proteins. We identified microtubule associated protein 1b (MAP1B) to be specifically enriched in podocytes in human and rodent kidney. Using immunogold labeling in electron microscopy, we were able to demonstrate an enrichment of MAP1B in primary processes. A similar association of MAP1B with the microtubule cytoskeleton was detected in cultured podocytes. Subcellular distribution of MAP1B HC and LC1 was analyzed using a double fluorescent reporter MAP1B fusion protein. Subsequently we analyzed mice constitutively depleted of MAP1B. Interestingly, MAP1B KO was not associated with any functional or structural alterations pointing towards a redundancy of MAP proteins in podocytes. In summary, we established MAP1B as a specific marker protein of the podocyte microtubular cytoskeleton.
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Gödel
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Dunja
authors.initials: D
authors.lastname: Temerinac
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Grahammer
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Hartleben
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany; Department of Neuroanatomy, Albert-Ludwigs-University Freiburg, Freiburg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kretz
authors.affiliation: Center for Psychiatric Neurosciences, Proteomics Unit, Psychiatric Hospital, CHUV, University of Lausanne, Prilly-Lausanne, Switzerland.
authors.forename: Beat M
authors.initials: BM
authors.lastname: Riederer
authors.affiliation: Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories (MFPL), University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Propst
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany; Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kohl
authors.affiliation: Renal Division, University Medical Center Freiburg, Freiburg, Germany; BIOSS Center for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany; Center for Systems Biology (ZBSA), Albert-Ludwigs-University Freiburg, Freiburg, Germany.
authors.forename: Tobias B
authors.initials: TB
authors.lastname: Huber
mesh_terms: D000818:Animals; D015415:Biomarkers; D002478:Cells, Cultured; D005260:Female; D060730:Glomerular Filtration Barrier / Q000378:metabolism*; D005919:Glomerular Filtration Rate; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D009928:Organ Specificity; D050199:Podocytes / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D015415:Biomarkers; D008869:Microtubule-Associated Proteins; C085284:microtubule-associated protein 1B