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Deep mapping of the podocyte proteome unravels altered protein dynamics during differentiation
Author(s) -
Schroeter Christina,
Benzing Thomas,
Brinkkötter Paul,
Rinschen Markus
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1006.1
Subject(s) - podocyte , microbiology and biotechnology , proteome , cellular differentiation , receptor , biology , cytoskeleton , cell , chemistry , biochemistry , kidney , genetics , gene , proteinuria
Podocytes are epithelial postmitotic cells which maintain the renal filtration barrier. Immortalized mouse and human podocyte cell lines‐both in the differentiated and undifferentiated state‐are widely utilized tools to estimate podocyte injury and cytoskeletal rearrangement processes in vitro. Here, we mapped the cultured podocyte proteome of both mouse and human origin at a depth of more than 8800 proteins in the differentiated and undifferentiated state, respectively. We performed comparative analyses of both “deep” proteomic profiles. Cultured podocytes express abundant copy numbers of endogenous receptors, such as tyrosine kinase membrane receptors, the G protein‐coupled receptor (GPCR), NPR3 (ANP receptor), and several poorly characterized GPCRs. Some protein classes associated with podocyte disease, such as slit‐diaphragm associated proteins and ion channels, were hardly detected. Differentiation‐induced changes were comparable in mouse and human podocytes, but slight differences, e.g. in proteins associated with lipid metabolism were detected. Notably, this data set detected general perturbations in proteostatic mechanisms as a dominant alteration during podocyte differentiation irrespectively of the species: Proteasome activity and kinetics were high in the undifferentiated state and lysosomal activity was high in the differentiated state. Proteome‐wide stability measurements in differentiated and undifferentiated podocytes demonstrated preferential degradation mechanisms in each state, which may partially explain the cellular morphology of each state. In conclusion, podocyte differentiation in vitro is largely associated with a proteostatic shift, and the deep proteomic mapping approach utilized here may demonstrate the limitations, but also the potential of podocyte cell culture.