Assaying WAVE and WASH complex constitutive activities toward the Arp2/3 complex

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• The Arp2/3 complex is crucial for generating branched actin networks, essential for cellular processes.
• Nucleation Promoting Factors (NPFs), including WAVE and WASH proteins, activate the Arp2/3 complex.
• WAVE proteins regulate lamellipodia and ruffle formation, while WASH proteins are involved in endosome fission.

Purpose of the Study:

• To establish an efficient protocol for purifying WAVE and WASH complexes from human cell lines.
• To develop methods for verifying the integrity and activity of these purified complexes.
• To provide a quantitative assay for measuring the activity of WAVE and WASH complexes on the Arp2/3 complex.

Main Methods:

• Purification of WAVE and WASH complexes from human stable cell lines.
• Assessment of complex integrity using methods to detect aggregation.
• Quantification of NPF activity using the pyrene actin assay.
• Modification of the purification protocol to detect endogenous WAVE complex activity.

Main Results:

• An efficient protocol for purifying functional WAVE and WASH complexes was established.
• Methods to ensure the absence of aggregation in purified complexes were validated.
• The pyrene actin assay was successfully employed to measure Arp2/3 complex activation by purified NPFs.
• A modified protocol allows for the detection of endogenous WAVE complex activity.

Conclusions:

• The developed protocol provides a reliable method for studying the constitutive and endogenous activity of WAVE and WASH complexes.
• This research facilitates a deeper understanding of actin network regulation by NPFs.
• The protocol offers an accessible tool for assessing WAVE complex activation in cellular contexts.