Transcriptional Control of Cytoskeletal Remodeling, Mechanotransduction, and Cell Motility

Cell migration and adhesion initiates by traction generation through reciprocal actomyosin tension and focal adhesion reinforcement, but continued motility requires adaptive cytoskeletal remodeling and adhesion release. Here, we asked whether de novo gene expression contributes to this cytoskeletal feedback. We found that global inhibition of transcription or translation does not impair initial spreading, polarization, or migration initiation, but causes eventual migratory arrest through excessive cytoskeletal tension and over-maturation of focal adhesions, tethering cells to their matrix. Persistent transcription limits global actin polymerization, but instantaneous transcription inhibition does not affect lamellipodia dynamics during attachment. Transcription limits adhesion formation on compliant substrates at short time-scales (< 4 hours), but is required for long-term (> 4 – 24 hours) adhesion remodeling on rigid substrates.

We identified the transcriptional coactivators YAP and TAZ as mediators of cytoskeletal-transcriptional feedback. YAP and TAZ modulate cell mechanics by limiting cytoskeletal and focal adhesion maturation to enable persistent cell motility. YAP/TAZ depletion increases adhesion maturation and actin polymerization, without affecting lamellipodial dynamics during cell attachment, consistent with global transcription inhibition. YAP and TAZ promote adhesion formation on compliant hydrogels at short time scales. However, long-term (> 4hrs) focal adhesion remodeling on rigid substrates requires YAP/TAZ-dependent gene expression.

YAP/TAZ-dependent target genes were found to regulate cytoskeletal remodeling through a Rho-ROCK-myosin II signaling axis. Motile arrest as a consequence of cytoskeletal maturation, after YAP/TAZ ablation, is partially rescued by depletion of the YAP/TAZ-dependent myosin phosphatase regulator, NUAK2, or by inhibition of Rho-ROCK-myosin II. This feedback loop was shown to be required for endothelial tube formation, sprouting angiogenesis, and vasculogenesis. Together, these data establish a transcriptional feedback axis necessary to maintain a responsive cytoskeletal equilibrium to enable persistent endothelial migration and function.