Related Experiment Video

Updated: Aug 8, 2026

Characterization at the Molecular Level using Robust Biochemical Approaches of a New Kinase Protein
11:23

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

Published on: June 30, 2019

LKB1-dependent signaling pathways

Dario R Alessi1, Kei Sakamoto, Jose R Bayascas

  • 1Medical Research Council, Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland. d.r.alessi@dundee.ac.uk

Annual Review of Biochemistry
|June 8, 2006
PubMed

Insights

The LKB1 protein kinase, mutated in Peutz-Jeghers cancer syndrome, acts as a tumor suppressor by regulating cell energy, polarity, and proliferation. Its activity is controlled by STRAD and MO25 interactions, impacting cellular pathways.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Peutz-Jeghers syndrome is a hereditary cancer predisposition syndrome linked to mutations in the LKB1 gene.
  • LKB1 (Liver kinase B1) is a serine/threonine kinase crucial for cellular energy homeostasis and tumor suppression.
  • Understanding LKB1's tumor suppressor mechanisms is vital for developing new cancer therapies.

Purpose of the Study:

  • To review recent findings on the tumor suppressor functions of the LKB1 protein kinase.
  • To elucidate the regulatory mechanisms controlling LKB1's cellular localization and activity.
  • To explore LKB1's role in cell polarity and energy sensing.

Main Methods:

  • Review of genetic and biochemical studies on LKB1.
  • Analysis of LKB1 interactions with STRAD and MO25.
  • Examination of LKB1's downstream signaling pathways.

Main Results:

  • LKB1's tumor suppressor activity involves regulating cell proliferation, polarity, and energy metabolism.
  • LKB1 localization and activity are modulated by its interaction with STRAD and MO25.
  • LKB1 phosphorylates and activates 14 AMP-activated protein kinase (AMPK)-related kinases.

Conclusions:

  • LKB1 is a critical tumor suppressor with multifaceted roles beyond proliferation control.
  • The LKB1-STRAD-MO25 complex represents a key regulatory hub in cellular signaling.
  • Studying Peutz-Jeghers syndrome has revealed novel pathways relevant to multiple diseases.

More Related Videos

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer06:51

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer

Published on: July 21, 2018

Rab10 Phosphorylation Detection by LRRK2 Activity Using SDS-PAGE with a Phosphate-binding Tag08:55

Rab10 Phosphorylation Detection by LRRK2 Activity Using SDS-PAGE with a Phosphate-binding Tag

Published on: December 14, 2017

Related Concept Videos

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...
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 the...
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...
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...
NF-κB-dependent Signaling Pathway02:26

NF-κB-dependent Signaling Pathway

The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
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...