Abstract: SA-PO303

Alpha-Actinin-4 Is Required for Shp2 Activation in Podocytes

Session Information

Category: Cell Biology

  • 204 Extracellular Matrix Biology, Fibrosis, Cell Adhesion

Author

  • Lee, Hsiao-Hui, National Yang-Ming University, Taipei, Taiwan
Background

Integrins mediate cell-matrix interaction and form focal adhesion (FA) to connect with cytoskeleton in adherent cells. Previously, we found that Shp2 promotes ROCKII activation that facilitates FA maturation and stress fibers orientation to optimize cellular tension in response to the increase of matrix rigidity.

Results

In this study, we identified that α-actinin-4 interacts with Shp2 at FAs in mouse embryonic fibroblasts by an in vitro pull-down assay with recombinant Shp2 N-SH2 domain. This interaction between endogenous Shp2 and α-actinin-4 at FAs was confirmed by co-immunoprecipitation and proximity ligation assay. Since α-actinin-4 plays an important role in podocytes adhesion, we then used a mouse temperature-inducible podocyte line and found that differentiated podocytes exhibited distinct FAs and stress fibers with the hyperactivation of Shp2 and ROCKII. Knockout of ACTN4, which encodes α-actinin-4, by CRISPR/Cas9 reduced Shp2 activation significantly in podocytes. Furthermore, inhibition of Shp2 reduced ROCKII activation, FAs, stress fibers, and BSA-filtration ability of podocytes.

Conclusion

Taken together, our results suggest the essential role of α-actinin-4 in Shp2 activation that is crucial for the cell adhesion and filtration function in podocytes.

Funding

  • Government Support - Non-U.S.