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Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
A palmitoylation switch mechanism regulates Rac1 function and membrane organization.
Inmaculada Navarro-Lérida1, Sara Sánchez-Perales, María Calvo
1Department of Vascular Biology, Integrin Signaling Laboratory, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
The EMBO Journal
|December 14, 2011
Summary
Palmitoylation of Rac1, a small GTPase, targets it to specific membrane regions, which is crucial for actin cytoskeleton organization and cell migration. This modification ensures proper Rac1 function in cellular processes.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The small GTPase Rac1 is vital for cellular functions like cytoskeletal reorganization and cell migration.
- Rac1 signaling initiation depends on GTP/GDP cycling and localization to ordered membrane microdomains.
- Molecular mechanisms controlling Rac1 compartmentalization remain largely unknown.
Purpose of the Study:
- To investigate the molecular mechanisms governing Rac1's specific membrane compartmentalization.
- To identify the role of post-translational modifications in Rac1 localization and function.
Main Methods:
- Investigated Rac1 palmitoylation at cysteine 178.
- Assessed the impact of palmitoylation on Rac1 targeting to detergent-resistant membranes (DRMs).
- Analyzed cell spreading and migration in Rac1-deficient or palmitoylation-deficient cells.
Main Results:
- Rac1 incorporates palmitate at cysteine 178, targeting it to ordered membrane regions linked to the actin cytoskeleton.
- Palmitoylation requires prior prenylation and an intact C-terminal polybasic region, regulated by a triproline-rich motif.
- Non-palmitoylated Rac1 exhibits reduced GTP loading and diminished association with DRMs, leading to altered membrane domain organization and impaired cell migration.
Conclusions:
- Palmitoylation is identified as a key mechanism regulating Rac1 function in actin cytoskeleton remodeling.
- This post-translational modification controls Rac1 membrane partitioning, which in turn influences overall membrane organization and cell motility.
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