A single discrete Rab5-binding site in phosphoinositide 3-kinase β is required for tumor cell invasion.

ABSTRACT: 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 (Gln⁵⁹⁶ and Ile⁵⁹⁷) 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-Rab5^GTP 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 perpendicula

SUBMITTER: Heitz SD 

PROVIDER: S-EPMC6433078 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature