Related Experiment Video
Updated: Oct 26, 2026

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
A Modular Optogenetic Split-Small GTPase Platform Reveals Long-Range RhoA Signaling
Benjamin Faulkner1, Yuchen He1, Daniel Sitrin1
1Department of Chemistry, University of Virginia, Charlottesville, Virginia22904, United States.
Abstract:
Small GTPases are critical regulators of cellular processes such as cell migration. However, no generalizable method exists for directly controlling their activity with subcellular precision, limiting the ability to dissect long-range signaling effects. To address this, we pair fragmented small GTPases with improved light-inducible dimerization (iLID) domains, optimizing for low dark-state background and efficient light-induced reassembly, affording spLIT-small GTPases. Demonstrating modularity, we control filopodia formation (spLIT-Cdc42), cell movement (spLIT-Rac1), and membrane retraction (spLIT-RhoA) with subcellular precision. Applying this platform to long-range signaling, we provide the first demonstration that localized RhoA activation is sufficient to drive membrane retraction at the opposite cell pole, with a directional dependence set by actin cytoskeleton polarization, a result inaccessible to global perturbations used previously. These results suggest a mechanism for coordinated establishment of cell polarity and highlight spLIT-small GTPases as a versatile platform for the direct, spatial control of small GTPase signaling in living cells.
Related Concept Videos
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:
Cell Polarization by Rho Proteins
Activation and Inactivation of G Proteins
Rab Cascades
GTPases and their Regulation
Large G-proteins, also known...
Coat Assembly and GTPases
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...

