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Updated: Aug 2, 2026
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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
The Arf GTPase-activating protein ASAP1 regulates the actin cytoskeleton
P A Randazzo1, J Andrade, K Miura
1Division of Basic Sciences, National Cancer Institute, Bethesda, MD 20892, USA. randazzo@helix.nih.gov
Summary
ASAP1, a protein regulating cell movement, localizes to focal adhesions. Its GTPase-activating protein activity is crucial for cell spreading and cytoskeletal remodeling in response to growth factors like PDGF.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Arf GTP-binding proteins are key regulators of membrane traffic.
- Emerging evidence suggests Arf proteins also play a role in cytoskeletal organization.
- ASAP1 (centaurin beta4) is an Arf GTPase-activating protein interacting with Arf, Src, and phosphatidylinositol 4,5-bisphosphate.
Purpose of the Study:
- To investigate the role of ASAP1 in cytoskeletal remodeling.
- To determine ASAP1's localization and dynamics within focal adhesions.
- To elucidate ASAP1's function in cell spreading and ruffle formation induced by platelet-derived growth factor (PDGF).
Main Methods:
- Cell culture and stimulation with PDGF.
- Overexpression of wild-type and mutant ASAP1.
- Microscopy to observe focal adhesion morphology, cell spreading, and dorsal ruffle formation.
Main Results:
- ASAP1 localizes to and cycles with focal adhesion proteins during cell migration.
- Overexpression of ASAP1 inhibits cell spreading and PDGF-induced dorsal ruffles.
- A mutant ASAP1 lacking GTPase-activating protein activity shows reduced inhibition of cell spreading and increased dorsal ruffles.
Conclusions:
- ASAP1 functions as a regulator of cytoskeletal remodeling through its GTPase-activating protein activity.
- The Arf pathway, specifically involving ASAP1, is implicated as a target of PDGF signaling.
- ASAP1 plays a critical role in controlling cell morphology and movement dynamics.
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