We have located links that may give you full text access.
A Single Discrete Rab5 Binding Site in PI3Kβ is Required for Tumor Cell Invasion.
Journal of Biological Chemistry 2019 January 19
Phosphoinositide 3-kinase β (PI3Kβ) is regulated by receptor tyrosine kinases (RTKs), G protein-coupled receptors (GPCRs), and small GTPases such as Rac1 and Rab5. Our lab previously identified two residues (Gln-596 and Ile-597) in the helical domain of the catalytic subunit (p110β) of PI3Kβ whose mutation disrupts binding to Rab5. To better define the Rab5-p110β interface, we performed alanine-scanning mutagenesis and analyzed Rab5 binding with an in vitro pulldown assay with GST-Rab5GTP Of the 35 p110β helical domain mutants assayed, 11 disrupted binding to Rab5 without affecting Rac1 binding, basal lipid kinase activity, or Gβγ-stimulated kinase activity. These mutants defined the Rab5-binding interface within p110β as consisting of two perpendicular α-helices in the helical domain that are adjacent to the initially identified Gln-596 and Ile-597 residues. Analysis of the Rab5-PI3Kβ interaction by hydrogen-deuterium exchange MS identified p110β peptides that overlap with these helices; no interactions were detected between Rab5 and other regions of p110β or p85α. Similarly, the binding of Rab5 to isolated p85α could not be detected, and mutations in the Ras-binding domain (RBD) of p110β had no effect on Rab5 binding. Whereas soluble Rab5 did not affect PI3Kβ activity in vitro , the interaction of these two proteins was critical for chemotaxis, invasion, and gelatin degradation by breast cancer cells. Our results define a single, discrete Rab5-binding site in the p110β helical domain and may be useful for generating inhibitors to better define the physiological role of Rab5-PI3Kβ coupling in vivo .
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app