[HTML][HTML] Positive and negative roles of p85α and p85β regulatory subunits of phosphoinositide 3-kinase in insulin signaling

K Ueki, DA Fruman, CM Yballe, M Fasshauer… - Journal of Biological …, 2003 - ASBMB
Class IA phosphoinositide (PI) 3-kinase is composed of a p110 catalytic subunit and a p85
regulatory subunit and plays a pivotal role in insulin signaling. To explore the physiological
roles of two major regulatory isoforms, p85α and p85β, we have established brown adipose
cell lines with disruption of the Pik3r1 or Pik3r2 gene. Pik3r1-/-(p85α-/-) cells show a 70%
reduction of p85 protein and a parallel reduction of p110. These cells have a 50% decrease
in PI 3-kinase activity and a 30% decrease in Akt activity, leading to decreased insulin …