| TUBA1A Protein | |
|---|---|
| Protein Name | Tubulin Alpha 1A |
| Gene | [TUBA1A](/entities/tuba1a) |
| UniProt ID | [P68366](https://www.uniprot.org/uniprot/P68366) |
| PDB ID | 1JFF, 4I55 |
| Molecular Weight | ~50.1 kDa (451 amino acids) |
| Subcellular Localization | Cytoskeleton, microtubules |
| Protein Family | Tubulin superfamily, alpha-tubulin |
| Associated Diseases | Lissencephaly type 3, cortical dysplasia |
TUBA1A (Tubulin Alpha 1A) encodes the most abundantly expressed alpha-tubulin isotype in the developing and adult brain[1]. Alpha- and beta-tubulin heterodimers polymerise to form microtubules — the major cytoskeletal scaffold of neurons. Microtubules are essential for neuronal migration, axon guidance, intracellular transport, synaptic function, and cell division. Dominant TUBA1A mutations cause a spectrum of brain malformations collectively termed tubulinopathies, ranging from severe lissencephaly to subtle cortical dysplasia with intellectual disability and epilepsy[2]. Beyond developmental disorders, TUBA1A and the broader tubulin–microtubule system are increasingly recognised as relevant to neurodegenerative diseases where tau-mediated microtubule destabilisation, axonal transport failure, and cytoskeletal collapse are central pathogenic mechanisms[3].
TUBA1A is a 451-amino-acid protein with the canonical tubulin fold[1:1]:
The crystal structure at 3.5 Å resolution reveals that most disease-causing mutations cluster at the heterodimer interface, the longitudinal contacts between dimers, or the binding surfaces for MAPs and motor proteins[2:1].
TUBA1A heterodimers undergo dynamic instability — stochastic switching between growth and shrinkage phases at the plus-end[1:2]:
During cortical development, TUBA1A is the predominant alpha-tubulin in migrating neurons[2:2]:
Microtubules built from TUBA1A serve as the rails for long-range intracellular transport[3:1]:
In mature neurons with axons exceeding 1 metre (motor neurons), microtubule-based transport is the sole mechanism for supplying distant synapses with proteins, mitochondria, and RNA.
At synapses, dynamic TUBA1A-containing microtubules transiently invade dendritic spines, delivering cargo and influencing spine morphology and synaptic plasticity[5]:
Dominant TUBA1A mutations cause a spectrum of malformations with neurodegeneration-like features[2:3][6]:
| Phenotype | Features | Common Mutations |
|---|---|---|
| Lissencephaly type 3 | Smooth brain, absent gyri, severe ID, epilepsy | R264C, R402H |
| Pachygyria | Thick gyri, moderate ID | Various missense |
| Polymicrogyria | Excessive small gyri, variable ID | P263L |
| Cortical dysplasia with cerebellar hypoplasia | Motor delay, ataxia, ID | L286F, R422H |
These mutations disrupt heterodimer folding (via chaperonin cofactor interactions), microtubule dynamics, or MAP/motor protein binding[6:1].
TUBA1A is directly relevant to tauopathies because tau is a microtubule-associated protein that binds the tubulin lattice[3:2]:
Microtubule destabilisation in neurodegeneration causes a cascade of transport failures[3:3][8]:
Alpha-synuclein oligomers bind tubulin directly and impair microtubule polymerisation in vitro[9]. In LRRK2-G2019S PD models, hyperactive LRRK2 kinase phosphorylates tubulin-associated proteins, disrupting microtubule stability in dopaminergic neuron axons.
The tubulin code is altered in neurodegenerative disease[4:2]:
For severe TUBA1A lissencephaly, antisense or gene replacement strategies are being explored in preclinical models, though the dominant-negative nature of most mutations complicates simple supplementation approaches.
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Bahi-Buisson N et al. The wide spectrum of tubulinopathies: what are the key features for the diagnosis?. Brain. 2014. ↩︎ ↩︎ ↩︎ ↩︎
Brandt R, Bhatt P. Microtubule dynamics and the neurodegenerative triad of Alzheimer's disease. International Journal of Molecular Sciences. 2020. ↩︎ ↩︎ ↩︎ ↩︎
Janke C, Magiera MM. The tubulin code and its role in controlling microtubule properties and functions. Nature Reviews Molecular Cell Biology. 2020. ↩︎ ↩︎ ↩︎
Jaworski J et al. Dynamic microtubules regulate dendritic spine morphology and synaptic plasticity. Neuron. 2009. ↩︎
Keays DA et al. Mutations in alpha-tubulin cause abnormal neuronal migration in mice and lissencephaly in humans. Cell. 2007. ↩︎ ↩︎
Zhang F et al. Posttranslational modifications of alpha-tubulin in Alzheimer disease. Translational Neurodegeneration. 2015. ↩︎
Zhang B et al. The microtubule-stabilizing agent, epothilone D, reduces axonal dysfunction, neurotoxicity, cognitive deficits, and Alzheimer-like pathology in an interventional study with aged tau transgenic mice. Journal of Neuroscience. 2012. ↩︎ ↩︎ ↩︎
Cartelli D et al. Alpha-synuclein is a novel microtubule dynamase. Scientific Reports. 2016. ↩︎
Boxer AL et al. Davunetide in patients with progressive supranuclear palsy: a randomised, double-blind, placebo-controlled phase 2/3 trial. The Lancet Neurology. 2014. ↩︎