ARHGAP42 is activated by Src-mediated tyrosine phosphorylation to promote cell motility

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• The tyrosine kinase Src regulates cell motility by phosphorylating proteins involved in cytoskeletal dynamics.
• ARHGAP42, a Rho-GTPase activating protein (GAP), was identified as a potential Src substrate.
• ARHGAP42 features BAR-PH domains N-terminal to its GAP domain and primarily targets RhoA.

Purpose of the Study:

• To investigate the regulation of ARHGAP42 by Src phosphorylation.
• To elucidate the role of ARHGAP42 domains in its GAP activity and cellular function.
• To understand how Src-mediated phosphorylation of ARHGAP42 influences cell motility.

Main Methods:

• Phosphotyrosine proteomics to identify Src substrates.
• Expression of ARHGAP42 variants in mammalian cells.
• Analysis of RhoA activity and cell motility.

Main Results:

• Src primarily phosphorylates ARHGAP42 at tyrosine 376 (Tyr-376).
• Deletion of the BAR domain of ARHGAP42 inhibited its GAP activity, decreasing RhoA and increasing cell motility.
• Phosphorylation of ARHGAP42 Tyr-376 by Src activated its GAP activity, promoting cell motility.

Conclusions:

• Src phosphorylation of ARHGAP42 at Tyr-376 is a novel regulatory mechanism.
• This phosphorylation event activates ARHGAP42's RhoA inhibitory function.
• The Src-ARHGAP42 pathway regulates actin dynamics and promotes cell motility.