ABSTRACT
Desmosomes play a crucial role in maintaining tissue barrier integrity, particularly in mechanically stressed tissues. The assembly of desmosomes is regulated by the cytoskeleton and its regulators, and desmosomes also function as a central hub for regulating F-actin. However, the specific mechanisms underlying the crosstalk between desmosomes and F-actin remain unclear. Here, we identified that ARHGAP32, a Rho GTPase-activating protein, is located in desmosomes through its interaction with desmoplakin (DSP) via its GAB2-interacting domain (GAB2-ID). We confirmed that ARHGAP32 is required for desmosomal organization, maturation and length regulation. Notably, loss of ARHGAP32 increased formation of F-actin stress fibers and phosphorylation of the regulatory myosin light chain Myl9 at T18/S19. Inhibition of ROCK activity in ARHGAP32-knockout (KO) cells effectively restored desmosomal organization and the integrity of epithelial cell sheets. Moreover, loss of DSP impaired desmosomal ARHGAP32 location and led to decreased actomyosin contractility. ARHGAP32 with a deletion of the GAB2-ID domain showed enhanced association with RhoA in the cytosol and failed to rescue the desmosomal organization in ARHGAP32-KO cells. Collectively, our study unveils that ARHGAP32 associates with and regulates desmosomes by interacting with DSP. This interaction potentially facilitates the crosstalk between desmosomes and F-actin.
Footnotes
Author contributions
Conceptualization: H.L., W.N.; Methodology: H.L., Y.H., Y.W., L.X.; Software: Y.H., Y.W., X.L., W.N.; Validation: L.X., G.W., X.L., X.D., K.Z.; Formal analysis: H.L., Y.H., Y.W., L.X., W.N.; Investigation: H.L., Y.H., Y.W., L.X., G.W., X.L., X.D., K.Z.; Resources: W.N.; Writing - original draft: H.L., W.N.; Writing - review & editing: H.L., Y.H., X.L., W.N.; Visualization: H.L., Y.H., Y.W., X.L., W.N.; Supervision: H.L., W.N.; Project administration: W.N.; Funding acquisition: H.L., W.N.
Funding
This study was supported by the National Natural Science Foundation of China (no. 32270846), Yunnan Provincial Department of Education (no. 2023J0003), and the Applied Basic Research Foundation of Yunnan Province (no. 202301AU070179, 202401AT070443).
Data availability
All relevant data can be found within the article and its supplementary information.
