Related Experiment Video

Updated: May 6, 2026

Amide Hydrogen/Deuterium Exchange & MALDI-TOF Mass Spectrometry Analysis of Pak2 Activation
07:15

Amide Hydrogen/Deuterium Exchange & MALDI-TOF Mass Spectrometry Analysis of Pak2 Activation

Published on: November 26, 2011

20.3K

Structure of PAK1 in an autoinhibited conformation reveals a multistage activation switch

M Lei1, W Lu, W Meng

  • 1Laboratory of Molecular Medicine, Children's Hospital, Boston, Massachusetts 02115, USA.

Cell
|September 7, 2000
PubMed

Insights

p21-activated kinases (PAKs) are regulated by GTPase binding, which disrupts their dimer structure. This conformational change activates the kinase domain, enabling downstream signaling pathways involved in cell structure and function.

Area of Science:

  • Molecular Biology
  • Cell Signaling
  • Structural Biology

Background:

  • p21-activated kinases (PAKs) are crucial regulators of cytoskeletal actin assembly and MAP-kinase pathways.
  • PAKs are activated by binding with GTP-liganded forms of Cdc42 or Rac.
  • The precise mechanism of PAK activation involves conformational changes.

Purpose of the Study:

  • To elucidate the structural basis of PAK1 activation by GTPases.
  • To understand the role of the N-terminal autoregulatory fragment and C-terminal kinase domain in PAK1 regulation.
  • To investigate the function of the inhibitory switch (IS) domain.

Main Methods:

  • X-ray crystallography at 2.3 A resolution.
  • Structural analysis of a complex between the N-terminal autoregulatory fragment and C-terminal kinase domain of PAK1.
  • Comparative analysis with related proteins like WASP.

Main Results:

  • GTPase binding triggers a cascade of conformational changes in PAK1.
  • Activation involves the disruption of the PAK1 dimer.
  • The kinase active site rearranges into a catalytically competent state.
  • The inhibitory switch (IS) domain undergoes refolding and unfolding upon GTPase binding.

Conclusions:

  • GTPase binding induces a significant conformational rearrangement of PAK1, leading to kinase activation.
  • The inhibitory switch domain plays a critical role in regulating PAK1 activity.
  • The findings provide insights into the activation mechanism of PAK family kinases.

More Related Videos

An Integrated System to Remotely Trigger Intracellular Signal Transduction by Upconversion Nanoparticle-mediated Kinase Photoactivation11:20

An Integrated System to Remotely Trigger Intracellular Signal Transduction by Upconversion Nanoparticle-mediated Kinase Photoactivation

Published on: August 30, 2017

6.8K
A Guide to Production, Crystallization, and Structure Determination of Human IKK1/α11:27

A Guide to Production, Crystallization, and Structure Determination of Human IKK1/α

Published on: November 2, 2018

7.8K

Related Concept Videos

Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
7.4K
Interactions Between Signaling Pathways01:19

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
4.7K
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
15.3K
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
7.3K
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
10.2K
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,...
5.0K