WT1-interacting protein and ZO-1 translocate into podocyte nuclei after puromycin aminonucleoside treatment
- 1 August 2005
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Renal Physiology
- Vol. 289 (2), F431-F441
- https://doi.org/10.1152/ajprenal.00389.2004
Abstract
Podocyte differentiation is required for normal glomerular filtration barrier function and is regulated by the transcription factor WT1. We identified WT1-interacting protein (WTIP) and hypothesized that it functions as both a scaffold for slit diaphragm proteins and a corepressor of WT1 transcriptional activity by shuttling from cell-cell junctions to the nucleus after injury. Endogenous WTIP colocalizes with zonula occludens-1 (ZO-1) in cultured mouse podocyte adherens junctions. To model podocyte injury in vitro, we incubated differentiated podocytes with puromycin aminonucleoside (PAN; 100 μg/ml) for 24 h, which disassembled cell-cell contacts, rearranged actin cytoskeleton, and caused process retraction. Podocyte synaptopodin expression diminished after PAN treatment, consistent with podocyte dedifferentiation in some human glomerular diseases. To assess podocyte function, we measured albumin flux across differentiated podocytes cultured on collagen-coated Transwell filters. Albumin transit across PAN-treated cells increased to levels observed with undifferentiated podocytes. Consistent with our hypothesis, WTIP, as well as ZO-1, translocated from podocyte adherens junctions to nuclei in PAN-treated cells. Because WTIP is a transcriptional corepressor for WT1, we examined the effect of PAN on expression of retinoblastoma binding protein Rbbp7 (also known as RbAp46), a WT1 target gene expressed in S-shaped bodies during nephrogenesis. Rbbp7 expression in PAN-treated podocytes was reduced compared with untreated cells. In conclusion, WTIP translocates from cell-cell junctions to the nucleus in PAN-treated podocytes. We suggest that WTIP monitors slit diaphragm protein assembly and shuttles into the nucleus after podocyte injury, translating changes in slit diaphragm structure into altered gene expression and a less differentiated phenotype.Keywords
This publication has 49 references indexed in Scilit:
- Tbx5 and Tbx4 transcription factors interact with a new chicken PDZ-LIM protein in limb and heart developmentDevelopmental Biology, 2004
- A WT1 Co-regulator Controls Podocyte Phenotype by Shuttling between Adhesion Structures and NucleusPublished by Elsevier BV ,2004
- Insights into the physiological role of WT1 from studies of genetically modified micePhysiological Genomics, 2004
- The Wilms' tumour protein (WT1) shuttles between nucleus and cytoplasm and is present in functional polysomesHuman Molecular Genetics, 2003
- Bcl-2 expression decreases cadherin-mediated cell-cell adhesionJournal of Cell Science, 2003
- Aurora-A and an Interacting Activator, the LIM Protein Ajuba, Are Required for Mitotic Commitment in Human CellsCell, 2003
- Targeting of Zyxin to Sites of Actin Membrane Interaction and to the NucleusPublished by Elsevier BV ,2001
- Transport Between the Cell Nucleus and the CytoplasmAnnual Review of Cell and Developmental Biology, 1999
- Podocytic degeneration and regeneration in puromycin aminonucleoside nephropathy in the ratPathology International, 1995
- Podocytes in glomerulus of rat kidney express a characteristic 44 KD protein.Journal of Histochemistry & Cytochemistry, 1991