STK11 - Serine/Threonine Kinase 11
Introduction
Pathway Diagram
flowchart TD
STK11["STK11<br/>Serine/Threonine<br/>Kinase 11"]
Crocetin["Crocetin<br/>Natural Compound"]
AMPK["AMPK<br/>AMP-activated<br/>Protein Kinase"]
MTOR["mTOR<br/>Mechanistic Target<br/>of Rapamycin"]
MTOR_Pathway["mTOR Pathway<br/>Activity"]
Copy_Loss["Copy Number<br/>Loss"]
Alzheimer["Alzheimer's<br/>Disease"]
ALS["Amyotrophic<br/>Lateral Sclerosis"]
MS["Multiple<br/>Sclerosis"]
Ataxia["Ataxia"]
Cancer["Cancer/<br/>Tumor"]
Neuroprotection["Neuroprotective<br/>Effects"]
Therapeutic["Therapeutic<br/>Target"]
Crocetin -->|"activates"| STK11
AMPK -->|"activates"| STK11
Copy_Loss -->|"associated with"| STK11
STK11 -->|"inhibits"| MTOR
STK11 -->|"inhibits"| MTOR_Pathway
STK11 -->|"inhibits"| Alzheimer
STK11 -->|"inhibits"| ALS
STK11 -->|"inhibits"| MS
STK11 -->|"regulates"| Ataxia
STK11 -->|"inhibits"| Cancer
STK11 -->|"leads to"| Neuroprotection
STK11 -->|"potential"| Therapeutic
style STK11 fill:#006494,color:#e0e0e0
style Crocetin fill:#1b5e20,color:#e0e0e0
style AMPK fill:#4a1a6b,color:#e0e0e0
style MTOR fill:#ef5350,color:#0d0d1a
style MTOR_Pathway fill:#ef5350,color:#0d0d1a
style Copy_Loss fill:#ef5350,color:#0d0d1a
style Neuroprotection fill:#1b5e20,color:#e0e0e0
style Therapeutic fill:#1b5e20,color:#e0e0e0
style Alzheimer fill:#5d4400,color:#e0e0e0
style ALS fill:#5d4400,color:#e0e0e0
style MS fill:#5d4400,color:#e0e0e0
style Ataxia fill:#5d4400,color:#e0e0e0
style Cancer fill:#5d4400,color:#e0e0e0
...STK11 - Serine/Threonine Kinase 11
Introduction
Pathway Diagram
Mermaid diagram (expand to render)
Stk11 Serine Threonine Kinase 11 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
<div class="infobox infobox-gene"> [@hawley2003]
<h3>STK11</h3> [@hardie2011]
<table> [@kuma2004]
<tr><th>Full Name</th><td>Serine/Threonine Kinase 11 (LKB1)</td></tr> [@egan2011]
<tr><th>Chromosome</th><td>19p13.3</td></tr> [@marinangeli2018]
<tr><th>NCBI Gene ID</th><td><a href="https://www.ncbi.nlm.nih.gov/gene/6794" target="_blank">6794</a></td></tr> [@vingtdeux2011]
<tr><th>OMIM</th><td><a href="https://www.omim.org/entry/602216" target="_blank">602216</a></td></tr> [@cant2019]
<tr><th>Ensembl ID</th><td><a href="https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000118046" target="_blank">ENSG00000118046</a></td></tr> [@shaw2009]
<tr><th>UniProt ID</th><td><a href="https://www.uniprot.org/uniprot/Q15831" target="_blank">Q15831</a></td></tr> [@hezel2008]
<tr><th>Protein Length</th><td>433 amino acids</td></tr> [@barnes2007]
<tr><th>Protein Family</th><td>STK11 family, AMPK-related kinases</td></tr>
<tr><th>Associated Diseases</th><td>Peutz-Jeghers Syndrome, Alzheimer's Disease, Parkinson's Disease, Cancer</td></tr>
</table>
</div>
Overview
STK11 (Serine/Threonine Kinase 11), more commonly known as LKB1 (Liver Kinase B1), is a master upstream kinase that plays a central role in cellular energy metabolism, stress responses, and cell polarity. LKB1 activates the AMPK (AMP-activated protein kinase) family of kinases, which serve as primary energy sensors that regulate metabolic homeostasis, autophagy, mitochondrial biogenesis, and cell growth.
In [neurons](/entities/neurons), LKB1 is essential for establishing neuronal polarity, axon specification, and synaptic function. Loss of LKB1 function contributes to neurodegeneration through impaired energy homeostasis, reduced autophagy, and altered mitochondrial dynamics. Germline mutations in STK11 cause Peutz-Jeghers Syndrome, a hereditary cancer predisposition syndrome, while somatic mutations are common in various cancers.
Gene Structure and Expression
The STK11 gene is located on chromosome 19p13.3 and encodes a serine/threonine protein kinase of 433 amino acids. The gene contains 9 exons and undergoes alternative splicing to produce multiple isoforms. LKB1 is ubiquitously expressed with high levels in epithelial cells, neurons, and metabolic tissues including liver, muscle, and adipose tissue.
Protein Structure and Function
LKB1 is a member of the CaMK (Calcium/Calmodulin-dependent Kinase) family but lacks calcium-binding domains:
Kinase Domain
- Catalytic domain in the N-terminus (residues 1-270)
- Binds ATP and phosphorylates target proteins
- Activity requires association with two accessory subunits: STRAD and MO25
Regulatory Features
- C-terminal domain mediates protein-protein interactions
- Dimerization is required for activity
- Phosphorylation at multiple sites regulates stability and function
Substrate Specificity
- Phosphorylates 14 AMPK family kinases (AMPKα1/α2, BRSK1/2, MARK1-4, NUAK1/2, SIK1-3, SNRK)
- Activates downstream pathways for energy homeostasis
Cellular Functions
Energy Sensing
- Activates AMPK when ATP levels fall (high AMP/ATP ratio)
- Triggers metabolic adaptation to restore energy balance
- Inhibits anabolic pathways (fatty acid synthesis, cholesterol synthesis)
- Activates catabolic pathways (fatty acid oxidation, autophagy)
- Increases glucose uptake via GLUT4 translocation
- Enhances fatty acid oxidation in mitochondria
- Promotes mitochondrial biogenesis via PGC-1α
- Regulates lipid metabolism
Autophagy Activation
- Phosphorylates and activates ULK1
- Initiates autophagy cascade
- Essential for mitophagy and clearance of damaged organelles
- Prevents accumulation of protein aggregates
Neuronal Functions
- Essential for neuronal polarity and axon specification
- Regulates microtubule dynamics
- Controls dendritic arborization
- Modulates synaptic plasticity
Disease Associations
Alzheimer's Disease
LKB1/AMPK dysfunction contributes to AD pathogenesis:
- Energy metabolism: Impaired glucose metabolism in AD brain
- [Autophagy](/entities/autophagy) defects: Reduced autophagic clearance of [Aβ](/proteins/amyloid-beta) and [tau](/proteins/tau)
- Mitochondrial dysfunction: Impaired mitochondrial biogenesis
- Synaptic failure: Altered synaptic plasticity mechanisms
- [mTOR](/entities/mtor) dysregulation: Cross-talk between LKB1-AMPK and [mTOR](/mechanisms/mtor-signaling-pathway) pathways
Parkinson's Disease
LKB1 implications in PD include:
- Mitophagy impairment: Reduced clearance of damaged mitochondria
- [α-synuclein](/proteins/alpha-synuclein) toxicity: Altered protein quality control
- Dopaminergic neuron vulnerability: Energy deficiency in SNc neurons
- LRRK2 interactions: LRRK2 can phosphorylate AMPK
Peutz-Jeghers Syndrome
- Autosomal dominant disorder caused by STK11 mutations
- Characterized by mucocutaneous pigmentation
- Gastrointestinal hamartomatous polyps
- Increased cancer risk (breast, colorectal, pancreatic, stomach)
Therapeutic Implications
Targeting LKB1-AMPK pathway offers therapeutic opportunities:
AMPK Activators
- Metformin: Indirect LKB1-AMPK activator (most widely used)
- AICAR: Direct AMPK agonist
- Natural compounds: Berberine, resveratrol
Direct LKB1 Modulators
- Small molecule LKB1 activators
- Gene therapy approaches
Combination Strategies
- LKB1 activation with autophagy enhancers
- Mitochondrial protectants combined with AMPK activators
- Metabolic modulators for neurodegeneration
Background
The study of Stk11 Serine Threonine Kinase 11 has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
See Also
- [Genes Index](/genes)
- [Proteins Index](/proteins)
- [Mechanisms Index](/mechanisms)
- [AMPK Signaling Pathway](/mechanisms/ampk-signaling-pathway)
- [Autophagy Pathway](/mechanisms/autophagy-lysosome-neurodegeneration)
- [Metabolic Dysfunction Pathway](/mechanisms/metabolic-dysfunction-pathway)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
External Links
- [NCBI Gene: STK11](https://www.ncbi.nlm.nih.gov/gene/6794)
- [UniProt: STK11](https://www.uniprot.org/uniprot/Q15831)
- [Ensemblhttps://www.](ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000118046)
- [Allen Brain Atlas: STK11 expression](https://portal.brain-map.org/)
References
[Woods A, et al, LKB1 is the upstream kinase in the AMPK-activated protein kinase cascade (2003)](https://pubmed.ncbi.nlm.nih.gov/14614842/)
[Hawley SA, et al, Complexes between the LKB1 tumor suppressor, STRAD alpha/beta and MO25 alpha/beta are upstream kinases in the AMP-activated protein kinase cascade (2003)](https://pubmed.ncbi.nlm.nih.gov/14511394/)
[Hardie DG, AMPK-sensing energy while talking to the thyroid (2011)](https://pubmed.ncbi.nlm.nih.gov/21747164/)
[Kuma A, et al, The role of autophagy during the early neonatal starvation period (2004)](https://pubmed.ncbi.nlm.nih.gov/15525940/)
[Egan DF, et al, Phosphorylation of ULK1 by AMPK initiates autophagy (2011)](https://pubmed.ncbi.nlm.nih.gov/22020285/)
[Marinangeli C, et al, AMPK in neurodegenerative diseases: implications for exercise (2018)](https://pubmed.ncbi.nlm.nih.gov/29901473/)
[Vingtdeux V, et al, AMPK is abnormally activated in tangle-bearing neurons in Alzheimer's disease (2011)](https://pubmed.ncbi.nlm.nih.gov/21205314/)
[Cantó C, et al, Energy homeostasis and its modification by behavioral interventions in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/31263254/)
[Shaw RJ, LKB1 and AMP-activated protein kinase control of mTORC1 and implications for cancer (2009)](https://pubmed.ncbi.nlm.nih.gov/19632571/)
[Hezel AF, et al, LKB1 deficiency in neurons leads to obesity and neurodegeneration (2008)](https://pubmed.ncbi.nlm.nih.gov/18337720/)
[Barnes AP, et al, LKB1 and AMPK regulate neuronal polarity and synaptic function (2007)](https://pubmed.ncbi.nlm.nih.gov/17640525/)Pathway Diagram
The following diagram shows the key molecular relationships involving STK11 - Serine/Threonine Kinase 11 discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)