Regulation of local GTP availability controls RAC1 activity and cell invasion

Anna Bianchi-Smiraglia, David W. Wolff, Daniel J. Marston, Zhiyong Deng, Zhannan Han, Sudha Moparthy, Rebecca M. Wombacher, Ashley L. Mussell, Shichen Shen, Jialin Chen, Dong Hyun Yun, Anderson O’Brien Cox, Cristina M. Furdui, Edward Hurley, Maria Laura Feltri, Jun Qu, Thomas Hollis, Jules Berlin Nde Kengne, Bernard Fongang, Rui J. SousaMikhail E. Kandel, Eugene S. Kandel, Klaus M. Hahn, Mikhail A. Nikiforov

Research output: Contribution to journalArticlepeer-review

Abstract

Physiological changes in GTP levels in live cells have never been considered a regulatory step of RAC1 activation because intracellular GTP concentration (determined by chromatography or mass spectrometry) was shown to be substantially higher than the in vitro RAC1 GTP dissociation constant (RAC1-GTP Kd). Here, by combining genetically encoded GTP biosensors and a RAC1 activity biosensor, we demonstrated that GTP levels fluctuating around RAC1-GTP Kd correlated with changes in RAC1 activity in live cells. Furthermore, RAC1 co-localized in protrusions of invading cells with several guanylate metabolism enzymes, including rate-limiting inosine monophosphate dehydrogenase 2 (IMPDH2), which was partially due to direct RAC1-IMPDH2 interaction. Substitution of endogenous IMPDH2 with IMPDH2 mutants incapable of binding RAC1 did not affect total intracellular GTP levels but suppressed RAC1 activity. Targeting IMPDH2 away from the plasma membrane did not alter total intracellular GTP pools but decreased GTP levels in cell protrusions, RAC1 activity, and cell invasion. These data provide a mechanism of regulation of RAC1 activity by local GTP pools in live cells.

Original languageEnglish (US)
Article number6091
JournalNature communications
Volume12
Issue number1
DOIs
StatePublished - Dec 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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