Related Experiment Video

Updated: Jun 4, 2026

Live-Cell Förster Resonance Energy Transfer Imaging of Metabolically Regulated Akt Activation Dynamics in HepG2 Cells
08:03

Live-Cell Förster Resonance Energy Transfer Imaging of Metabolically Regulated Akt Activation Dynamics in HepG2 Cells

Published on: May 23, 2025

Clk2 and B56β mediate insulin-regulated assembly of the PP2A phosphatase holoenzyme complex on Akt

Joseph T Rodgers1, Rutger O Vogel, Pere Puigserver

  • 1Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.

Molecular Cell
|February 19, 2011
PubMed

Insights

This study identifies Clk2 as a key regulator of Akt dephosphorylation, revealing how the PP2A phosphatase complex is assembled to attenuate Akt signaling. These findings enhance understanding of Akt regulation in cellular processes.

Area of Science:

  • Cellular signaling
  • Molecular biology
  • Biochemistry

Background:

  • Akt is crucial for cell growth, survival, and metabolism.
  • Akt activation mechanisms are well-studied, but its deactivation (attenuation) is poorly understood.

Purpose of the Study:

  • To elucidate the molecular mechanisms regulating Akt dephosphorylation.
  • To identify the components and dynamics involved in Akt signal attenuation.

Main Methods:

  • Investigated Clk2 as a downstream target of Akt activation.
  • Examined the role of Clk2 in recruiting and activating the PP2A phosphatase complex.
  • Analyzed the phosphorylation of the PP2A regulatory subunit B56β (PPP2R5B) by Clk2.
  • Assessed the effect on Akt phosphorylation sites (S473 and T308).

Main Results:

  • Clk2, a downstream target of Akt, triggers Akt dephosphorylation.
  • Clk2 phosphorylates the PP2A regulatory subunit B56β (PPP2R5B).
  • This phosphorylation is critical for PP2A holoenzyme assembly on Akt, leading to dephosphorylation at S473 and T308.

Conclusions:

  • Clk2 is a key mediator of Akt signal attenuation.
  • The Clk2-PP2A-B56β pathway is essential for regulating Akt activity.
  • These findings provide critical insights into the dynamics of Akt signaling regulation.

More Related Videos

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein11:23

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein

Published on: June 30, 2019

Related Concept Videos

PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
cAMP-dependent Protein Kinase Pathways01:25

cAMP-dependent Protein Kinase Pathways

Cyclic Adenosine Monophosphate (cAMP) is an essential second messenger that activates protein kinase A (PKA) and regulates various biological processes. A single epinephrine molecule binds to GPCR and activates several heterotrimeric G proteins, each stimulating multiple adenylyl cyclase, amplifying the signal, and synthesizing large numbers of cAMP molecules. Small changes in cAMP concentration affect PKA activity. The binding of four cAMP molecules induces a conformational change in PKA,...
Insulin: The Receptor and Signaling Pathways01:28

Insulin: The Receptor and Signaling Pathways

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
Calmodulin-dependent Signaling01:16

Calmodulin-dependent Signaling

Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.