Rab GTPases pp 271-281 | Cite as

Identification of the Rab5 Binding Site in p110β: Assays for PI3Kβ Binding to Rab5

  • Rachel S. Salamon
  • Hashem A. Dbouk
  • Denise Collado
  • Jaclyn Lopiccolo
  • Anne R. Bresnick
  • Jonthan M. BackerEmail author
Part of the Methods in Molecular Biology book series (MIMB, volume 1298)


Isoform-specific signaling by Class IA PI 3-kinases depends in part on the interactions between distinct catalytic subunits and upstream regulatory proteins. From among the class IA catalytic subunits (p110α, p110β, and p110δ), p110β has unique properties. Unlike the other family members, p110β directly binds to Gβγ subunits, downstream from activated G-protein coupled receptors, and to activated Rab5. Furthermore, the Ras-binding domain (RBD) of p110β binds to Rac and Cdc42 but not to Ras. Defining mutations that specifically disrupt these regulatory interactions is critical for defining their role in p110β signaling. This chapter describes the approach that was used to identify the Rab5 binding site in p110β, and discusses methods for the analysis of p110β-Rab5 interactions.

Key words

PIK3CB Class IA PI 3-kinase p110beta Rab5 Lipid kinases Phosphoinositide 3-kinases Small GTPases 


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Rachel S. Salamon
    • 1
  • Hashem A. Dbouk
    • 1
  • Denise Collado
    • 1
  • Jaclyn Lopiccolo
    • 1
  • Anne R. Bresnick
    • 3
  • Jonthan M. Backer
    • 1
    • 2
    Email author
  1. 1.Department of Molecular PharmacologyAlbert Einstein College of MedicineBronxUSA
  2. 2.Department of BiochemistryAlbert Einstein College of MedicineBronxUSA
  3. 3.Department of BiochemistryAlbert Einstein College of MedicineBronxUSA

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