Regulation of local GTP availability controls RAC1 activity and cell invasion.

Journal Article (Journal Article)

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.

Full Text

Duke Authors

Cited Authors

  • Bianchi-Smiraglia, A; Wolff, DW; Marston, DJ; Deng, Z; Han, Z; Moparthy, S; Wombacher, RM; Mussell, AL; Shen, S; Chen, J; Yun, D-H; O'Brien Cox, A; Furdui, CM; Hurley, E; Feltri, ML; Qu, J; Hollis, T; Kengne, JBN; Fongang, B; Sousa, RJ; Kandel, ME; Kandel, ES; Hahn, KM; Nikiforov, MA

Published Date

  • October 19, 2021

Published In

Volume / Issue

  • 12 / 1

Start / End Page

  • 6091 -

PubMed ID

  • 34667203

Pubmed Central ID

  • PMC8526568

Electronic International Standard Serial Number (EISSN)

  • 2041-1723

Digital Object Identifier (DOI)

  • 10.1038/s41467-021-26324-6


  • eng

Conference Location

  • England