Related Experiment Video

Updated: Dec 14, 2025

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry
08:07

Identification of Inositol Phosphate or Phosphoinositide Interacting Proteins by Affinity Chromatography Coupled to Western Blot or Mass Spectrometry

Published on: July 26, 2019

8.8K

Class IA PI3K regulatory subunits: p110-independent roles and structures

Millie Fox1, Helen R Mott1, Darerca Owen1

  • 1Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, U.K.

Biochemical Society Transactions
|July 18, 2020
PubMed

Insights

The phosphatidylinositol 3-kinase (PI3K) pathway is crucial for cell functions and frequently mutated in cancer. Free regulatory subunits (p85) have critical roles independent of PI3K, influencing cell signaling and homeostasis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The phosphatidylinositol 3-kinase (PI3K) pathway regulates vital cellular processes like survival, growth, and motility.
  • This pathway is frequently altered in human cancers, highlighting its significance.
  • Class IA PI3K regulatory subunits (p85) have functions beyond their canonical role in the PI3K holoenzyme.

Purpose of the Study:

  • To review the structure and functions of p110-independent class IA PI3K regulatory subunits.
  • To explore the critical roles of free p85 in cellular signaling and homeostasis.
  • To discuss the implications of p110-independent p85 dysregulation in disease.

Main Methods:

  • Literature review of existing research on PI3K pathway and p85 subunit.
  • Analysis of structural conformations and functional roles of p110-independent p85.
  • Discussion of factors influencing p85 monomer-dimer equilibrium.

Main Results:

  • p110-independent p85 exists in excess and has critical adaptor functions.
  • Free p85 influences signaling protein compartmentalization and sequestration.
  • p85 exhibits roles in glucose homeostasis, stress response, receptor trafficking, and cell migration.
  • Two distinct dimeric conformations of p85 are mediated by domain interactions.

Conclusions:

  • The monomer-dimer equilibrium of p110-independent p85 is critical for cellular function.
  • Disruption of this equilibrium can lead to disease.
  • Understanding p110-independent p85 structure and function is vital for therapeutic strategies.
Keywords:
cytoskeletonnuclear functionsp85phosphoinositide 3-kinasereceptor traffickingregulatory dimers

More Related Videos

A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors10:17

A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors

Published on: April 29, 2022

2.7K
Selected Reaction Monitoring Mass Spectrometry for Absolute Protein Quantification09:04

Selected Reaction Monitoring Mass Spectrometry for Absolute Protein Quantification

Published on: August 17, 2015

17.4K

Related Concept Videos

Phosphoinositides and PIPs01:42

Phosphoinositides and PIPs

Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs.
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
9.9K
IP3/DAG Signaling Pathway01:11

IP3/DAG Signaling Pathway

Membrane lipids such as phosphatidylinositol (PI) are precursors for several membrane-bound and soluble second messengers. Specific kinases phosphorylate PI and produce phosphorylated inositol phospholipids. One such inositol phospholipids are the  phosphatidylinositol-4,5 bisphosphate [PI(4,5)P2], present in the inner half of the lipid bilayer. Upon ligand binding, GPCR stimulates Gq proteins to turn on phospholipase Cꞵ. Activated phospholipase Cꞵ cleaves PI(4,5)P2 and...
13.8K
piRNA - Piwi-interacting RNAs02:57

piRNA - Piwi-interacting RNAs

PIWI-interacting RNAs, or piRNAs, are the most abundant short non-coding RNAs. More than 20,000 genes have been found in humans that code for piRNAs while only 2000 genes have been found for miRNAs. piRNAs can act at the transcriptional and post-transcriptional levels and have a vital role in silencing transposable elements present in germ cells. They are also involved in epigenetic silencing and activation. Previously, they were thought to function only in germ cells but new evidence suggests...
7.4K
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein....
8.4K
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

1.9K
Assembly of Signaling Complexes01:30

Assembly of Signaling Complexes

Multiprotein signaling complexes are formed in a dynamic process involving protein-protein interactions at the cytoplasmic domain of transmembrane receptors or enzymatic and non-enzymatic proteins associated with the receptor. These complexes ensure the activation and propagation of intracellular signals that regulate cell functions.
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
6.4K