Mechanosensitive turnover of phosphoribosyl pyrophosphate synthetases regulates nucleotide metabolism.

Cells coordinate their behaviors with the mechanical properties of the extracellular matrix (ECM). Tumor cells frequently harbor an enhanced nucleotide synthesis, presumably to meet the increased demands for rapid proliferation. Nevertheless, how ECM rigidity regulates nucleotide metabolism remains elusive. Here we show that shift from stiff to soft matrix blunts glycolysis-derived nucleotide synthesis in tumor cells. Soft ECM results in TNF receptor-associated factor 2 (TRAF2)-dependent K29 ubiquitination and degradation of phosphoribosyl pyrophosphate synthetase (PRPS)1/2. Recruitment of TRAF2 to PRPS1/2 requires phosphorylation of PRPS1 S285 or PRPS2 T285, which is mediated by low stiffness-activated large tumor suppressor (LATS)1/2 kinases. Further, non-phosphoryable or non-ubiquitinatable PRPS1/2 mutations maintain PRPS1/2 expression and nucleotide synthesis at low stiffness, and promote tumor growth and metastasis. Our findings demonstrate that PRPS1/2 stability and nucleotide metabolism is ECM rigidity-sensitive, and thereby highlight a regulatory cascade underlying mechanics-guided tumor metabolism reprogramming.