MAST1 Gene

MAST1 — Microtubule Associated Serine/Threonine Kinase 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">MAST1 Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>MAST1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Microtubule Associated Serine/Threonine Kinase 1</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>19p13.13</td>
</tr>
<tr>
<td class="label">Gene ID</td>
<td>23160</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000165633</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td>Q9P2N6</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>MAST, KIAA0973</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

Overview

MAST1 (Microtubule Associated Serine/Threonine Kinase 1), also known simply as MAST, is a large serine/threonine kinase that plays critical roles in cytoskeletal organization, synaptic function, and cellular signaling in the central nervous system. Originally identified as a scaffold protein in mast cells, MAST1 has emerged as a significant player in neuronal physiology and neurodegenerative disease pathogenesis[@hendriks2014].

The MAST family consists of three members (MAST1, MAST2, and MAST3) that share conserved domain architecture. MAST1 is particularly enriched in the brain, where it is expressed at high levels in regions associated with learning and memory, including the hippocampus and cerebral cortex.

MAST1 — Microtubule Associated Serine/Threonine Kinase 1

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">MAST1 Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>MAST1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Microtubule Associated Serine/Threonine Kinase 1</td>
</tr>
<tr>
<td class="label">Chromosome</td>
<td>19p13.13</td>
</tr>
<tr>
<td class="label">Gene ID</td>
<td>23160</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000165633</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td>Q9P2N6</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>MAST, KIAA0973</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

Overview

MAST1 (Microtubule Associated Serine/Threonine Kinase 1), also known simply as MAST, is a large serine/threonine kinase that plays critical roles in cytoskeletal organization, synaptic function, and cellular signaling in the central nervous system. Originally identified as a scaffold protein in mast cells, MAST1 has emerged as a significant player in neuronal physiology and neurodegenerative disease pathogenesis[@hendriks2014].

The MAST family consists of three members (MAST1, MAST2, and MAST3) that share conserved domain architecture. MAST1 is particularly enriched in the brain, where it is expressed at high levels in regions associated with learning and memory, including the hippocampus and cerebral cortex.

Gene Information

Structure and Evolution

Genomic Organization

The MAST1 gene spans approximately 70 kb on chromosome 19p13.13. The gene contains multiple exons and undergoes alternative splicing, generating several transcript variants. The coding sequence is evolutionarily conserved, with orthologs present in all vertebrate species.

Protein Domain Architecture

MAST1 is a large protein (~2000 amino acids) with multiple functional domains:

The kinase domain belongs to the CaMK (Calcium/Calmodulin-dependent Kinase) superfamily, sharing similarity with CaMKII and other serine/threonine kinases.

Normal Physiological Functions

Cytoskeletal Regulation

MAST1 plays important roles in cytoskeletal organization:

Microtubule Dynamics:

• Phosphorylates microtubule-associated proteins (MAPs)
• Modulates microtubule stability and polymerization
• Affects microtubule-based transport

• Regulates actin polymerization and depolymerization
• Affects cell morphology and migration
• Modulates dendritic spine structure

Synaptic Signaling

At synapses, MAST1 contributes to signaling complexes:

Postsynaptic Density:

• Associates with PSD-95 and other synaptic scaffolding proteins
• Modulates NMDA and AMPA receptor signaling
• Participates in long-term potentiation (LTP) and depression (LTD)

• Phosphorylates downstream effectors
• Integrates multiple signaling pathways
• Links membrane receptors to cytoskeletal changes

Kinase Activity

The catalytic activity of MAST1 phosphorylates multiple substrates:

• Tau protein: Phosphorylates tau at various sites
• MAP1B: Microtubule-associated protein 1B
• Synapsin: Synaptic vesicle protein
• Various scaffold proteins: Regulatory functions

Expression Pattern

Brain Expression

MAST1 is highly expressed in the central nervous system:

• Hippocampus: CA1-CA3 regions, dentate gyrus — highest expression
• Cerebral cortex: Layer V pyramidal neurons
• Cerebellum: Purkinje cells and granule cells
• Thalamus: Relay neurons
• Basal ganglia: Striatal medium spiny neurons
• Spinal cord: Motor neurons and interneurons

Cellular Localization

Within neurons, MAST1 localizes to:

• Dendrites: Throughout dendritic arborization
• Dendritic spines: Postsynaptic structures
• Axon initial segment: Initiation of action potentials
• Growth cones: During development and regeneration

Role in Alzheimer's Disease

Tau Phosphorylation

MAST1 has been directly implicated in tau pathology in Alzheimer's disease[@chen2018]:

Kinase Activity:

• MAST1 phosphorylates tau at multiple sites including Ser262, Ser396, and Thr231
• These phosphorylation events affect tau's ability to bind microtubules
• Hyperphosphorylated tau tends to aggregate into neurofibrillary tangles (NFTs)

• MAST1 expression is elevated in AD brain tissue
• MAST1 activity correlates with NFT burden
• Genetic variants in MAST1 may modify AD risk

Synaptic Dysfunction

MAST1 affects synaptic function in multiple ways[@li2019]:

Receptor Modulation:

• Phosphorylates NMDA receptor subunits
• Affects AMPA receptor trafficking
• Modulates metabotropic glutamate receptor signaling

• Regulates dendritic spine morphology
• Affects actin cytoskeleton in spines
• Contributes to spine loss in AD

Amyloid Interactions

The relationship between amyloid and MAST1 is complex:

• Direct phosphorylation: Amyloid-beta can affect MAST1 kinase activity
• Synaptic effects: MAST1 mediates some amyloid-induced synaptic deficits
• Signaling pathways: Both converge on similar downstream effectors

Therapeutic Target Potential

MAST1 represents a potential therapeutic target for AD[@wang2020]:

Kinase Inhibitors:

• Small molecule inhibitors of MAST1 catalytic activity
• Selective compounds with good brain penetration
• Combination strategies with other kinase inhibitors

• Allosteric modulators of MAST1 function
• Gene therapy approaches to reduce expression
• Antibody-based approaches

Role in Parkinson's Disease

Dopaminergic Neuron Function

In Parkinson's disease, MAST1 affects dopaminergic neurons in the substantia nigra[@kim2022]:

Neuronal Survival:

• Modulates survival signaling pathways
• Affects mitochondrial function
• Contributes to oxidative stress responses

• Regulates axonal transport
• Affects dopamine synthesis and release
• Modulates synaptic terminal function

Alpha-Synuclein Phosphorylation

MAST1 may phosphorylate alpha-synuclein:

• Kinase activity: MAST1 can phosphorylate α-syn at serine 129
• Aggregation: Phosphorylation affects aggregation kinetics
• Pathology: pSer129 α-syn is a major component of Lewy bodies

Therapeutic Implications

For PD, MAST1 targeting could involve:

• Neuroprotective strategies: Preserving dopaminergic neurons
• Aggregation modifiers: Affecting α-syn aggregation
• Synaptic protection: Maintaining functional terminals

Role in Other Neurodegenerative Diseases

Amyotrophic Lateral Sclerosis (ALS)

MAST1 may contribute to ALS through:

• Motor neuron function: Similar synaptic roles as in other neuronal populations
• Axonal transport: Important for long motor neuron axons
• Protein aggregation: May affect TDP-43 pathology

Epilepsy

Given its role in synaptic plasticity:

• Seizure susceptibility: Altered MAST1 affects neuronal excitability
• Temporal lobe epilepsy: Changes in hippocampal MAST1 expression

Multiple Sclerosis

MAST1 may play roles in demyelinating conditions:

• Oligodendrocyte function: Myelin maintenance
• Axonal degeneration: Common pathway in MS lesions

Therapeutic Implications

Drug Development

MAST1 is an attractive drug target:

Kinase Inhibitor Development:

• ATP-competitive inhibitors
• Allosteric modulators
• Covalent inhibitors for sustained inhibition

• Similarity to other CaMK family kinases
• Need for selectivity to avoid side effects
• Brain penetration requirements

Biomarker Potential

MAST1 as a biomarker:

• Peripheral measurement: Blood MAST1 levels
• Disease correlation: Changes with disease progression
• Therapeutic monitoring: Response to treatment

Combination Approaches

Given complex disease biology:

• Multi-target strategies: MAST1 plus other kinases
• Synergistic effects: Combined with amyloid or tau-targeted approaches
• Personalized medicine: Genetic variants affecting treatment response

Research Directions

Current Understanding

Key findings about MAST1 in neurodegeneration:

• Elevated expression in AD and PD brain
• Direct phosphorylation of tau and α-syn
• Role in synaptic dysfunction
• Potential as therapeutic target

Unresolved Questions

Several questions remain:

Research Tools

Advancing understanding requires:

• Selective antibodies: For detection and localization
• Activity assays: Measuring kinase function
• Animal models: Transgenic and conditional knockouts
• Inhibitor development: Tool compounds for research

Summary

MAST1 is a serine/threonine kinase with significant roles in neuronal function and neurodegeneration. Through its effects on tau phosphorylation, synaptic plasticity, and cytoskeletal regulation, MAST1 contributes to the pathogenesis of Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions.

The kinase activity of MAST1 makes it an attractive therapeutic target. Developing selective inhibitors that can modulate MAST1 function in the brain may provide new treatment options for these devastating diseases. However, significant research is needed to understand the full spectrum of MAST1 functions and develop effective, safe therapeutic approaches.

Molecular Mechanism

MAST1 (Microtubule Associated Serine/Threonine Kinase 1) is a 190-kDa cytoplasmic kinase consisting of an N-terminal CAP-Gly domain, a central series of HEAT repeats, and a C-terminal serine/threonine kinase domain that phosphorylates substrates involved in cytoskeletal dynamics and cell cycle regulation. MAST1 localizes to the centrosome and mitotic spindle during cell division and to dendritic shafts and postsynaptic densities in mature neurons, where it phosphorylates tau and other microtubule-associated proteins to regulate microtubule stability and dendritic spine morphology. Pathogenic de novo MAST1 variants cause mega-corpus-callosum syndrome with cerebellar hypoplasia and cortical malformations (Megalencephaly-Capillary Malformation Polymicrogyria syndrome spectrum), a neurodevelopmental disorder with progressive cerebellar atrophy reflecting impaired progenitor cell cycle exit and neuronal migration. MAST1 phosphorylates and activates the protein phosphatase 2A (PP2A) regulatory subunit, modulating the balance between kinase and phosphatase activities at synapses; dysregulated MAST1-PP2A signaling has been implicated in tau hyperphosphorylation and amyloid-β toxicity in Alzheimer's disease models. MAST3, a closely related family member, is genetically linked to epilepsy, and MAST1/MAST3 heteromers are expressed in cortical neurons, suggesting functional redundancy that masks phenotype severity when only one copy is disrupted. Therapeutic approaches include developing ATP-competitive MAST1 inhibitors and antisense oligonucleotides to reduce variant MAST1 expression. MAST1 also interacts with PSD-95 at excitatory synapses, where it scaffolds signaling complexes that regulate AMPA receptor trafficking during long-term potentiation. PMID: 32198973 PMID: 34185323 PMID: 32818970 PMID: 30449657 PMID: 18206861

References