Cell biology of osteoclasts II: PSTP1, an adaptor of protein tyrosine phosphatases, as a major component controlling of actin and sealing zone dynamics during bone degradation
Final Report Abstract
Through these two DFG funded projects, we have been able to illustrate the function of two key components FGD6 and PSTPIP1/3. Using MS-based quantitative proteomics, we have identified their key interactors. Using cell-based assays performed on osteoclasts treated with siRNA to depleted deplete osteoclasts of FGD6 or PSTPIP1/2 or their interactors, we could decipher fundamental molecular mechanisms allowing osteoclasts either to coordinate actin dynamics (podosome, sealing zone dynamics) and membrane traffic or podosome/sealing zone assembly/disassembly through SRC- and PTPN-dependent phosphorylation/dephosphorylation cycles. These studies have paved the way for a more systematic analysis of many other components that we have identified in our initial studies. Our studies also required the development of new methodologies of quantitative proteomic analyses (SILAC to identify Src or PTPN substrates, label free quantitative proteomics). These different methods developed in the context of these projects have been applied to other projects.
Publications
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(2014) The Cdc42 guanine nucleotide exchange factor FGD6 coordinates cell polarity and endosomal membrane recycling in osteoclasts. J Biol Chem. 289:18347-59
Charlotte Steenblock, Tobias Heckel, Cornelia Czupalla, Ana Isabel Espírito Santo, Christian Niehage, Martin Sztacho and Bernard Hoflack
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BAR Proteins PSTPIP1/2 Regulate Podosome Dynamics and the Resorption Activity of Osteoclasts.PLoS One. 2016 Oct 19;11(10):e0164829
Sztacho M, Segeletz S, Sanchez-Fernandez MA, Czupalla C, Niehage C, Hoflack B
