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Cellular localization of activated N-WASP using a conformation-sensitive antibody
P Sukumvanich1, V DesMarais, C V Sarmiento
1Department of Obstetrics, Gynecology, and Women's Health, Division of Gynecologic Oncology, Albert Einstein College of Medicine, Bronx, NY, USA.
Cell Motility and the Cytoskeleton
|September 14, 2004
Summary
Epidermal Growth Factor (EGF) stimulation activates N-WASP at the cell's leading edge, revealing its role in lamellipod formation. This study introduces a novel method to track protein activation dynamics.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- The Arp2/3 complex is crucial for actin nucleation, with N-WASP and Scar/WAVE proteins as key regulators.
- Understanding the spatiotemporal regulation of N-WASP activation is essential for deciphering cell motility and morphology.
- Carcinoma cell dynamics are influenced by actin cytoskeleton rearrangements, particularly at the leading edge.
Purpose of the Study:
- To investigate the recruitment and activation dynamics of N-WASP in carcinoma cells following EGF stimulation.
- To develop and validate a conformation-sensitive antibody (CSA) for detecting active N-WASP.
- To determine the localization of activated N-WASP within the cell during dynamic processes.
Main Methods:
- Utilized EGF stimulation in carcinoma cells to induce dynamic cellular responses.
- Developed a conformation-sensitive antibody (CSA) targeting the CRIB domain of N-WASP to distinguish active from inactive states.
- Performed in vitro experiments including immunoprecipitation and Cdc42 activation assays to validate CSA specificity.
- Conducted cell staining experiments to assess N-WASP accessibility to CSA and its localization.
Main Results:
- N-WASP is recruited to the leading edge nucleation zone within 1 minute of EGF stimulation, mirroring barbed-end formation.
- The conformation-sensitive antibody (CSA) specifically recognized active N-WASP, validated through in vitro assays.
- Activated N-WASP was detected at the leading edge of lamellipods approximately 40 seconds after EGF stimulation.
- The localization of activated N-WASP in lamellipods was an unexpected finding, contrasting with its known role in filopodia.
Conclusions:
- Active N-WASP is present in the nucleation zone of lamellipods, suggesting a role beyond filopodia formation.
- The study demonstrates the feasibility of using conformation-specific antibodies to track protein activation status and localization in real-time.
- This approach provides a novel window into the dynamic regulation of cellular processes involving N-WASP.