Rho GTPase-driven stress granules enable anchorage-independent survival under adhesion stress

Cells that lose adhesion to their native extracellular matrix must either adapt to impaired adhesion signaling or undergo anoikis. How cells convert loss of adhesion into translational stress responses and survival signaling remains incompletely understood. Here, we define adhesion stress as a cellular stress state triggered by impaired adhesion signaling and show that this state induces stress granule (SG) assembly as an adaptive survival mechanism. We modeled adhesion stress through cell detachment, reduced adhesion strength, and pharmacologic inhibition of focal adhesion kinase (FAK). Across these models, adhesion stress activated a RhoA-ROCK-PERK-eIF2α signaling pathway that drove SG assembly. PERK was the principal eIF2α kinase required for this adhesion-stress response. Proteomic profiling further showed that adhesion-stress SGs represent a previously unrecognized SG subtype characterized by a Rho GTPase-associated protein signature and selective enrichment of CASP4, an inflammatory caspase linked to cell-death signaling. Functionally, SG assembly limited CASP4 activation and reduced apoptotic signaling during FAK inhibitor-induced adhesion stress. In parallel, PERK contributed to sustained AKT-mTOR survival signaling during anoikis. Genetic loss of SG assembly or pharmacologic inhibition of G3BP-dependent SG formation increased anoikis sensitivity and sensitized cancer cells to multiple FAK inhibitors. SGs were also enriched in invading cancer cells in human breast tumors, consistent with a role for adhesion-stress adaptation in invasive tumor contexts. Together, these findings identify adhesion-stress SGs as a RhoA-ROCK-PERK-driven survival program that limits anoikis and enables anchorage-independent cancer cell survival.