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Saidin A, Papazovska Cherepnalkovski A, Shaukat Z, Arsov T, Hussain R, Roberts BJ, Bucat M, Cogelja K, Ricos MG, Dibbens LM. A Novel Pathogenic TUBA1A Variant in a Croatian Infant Is Linked to a Severe Tubulinopathy with Walker-Warburg-like Features. Genes (Basel) 2024; 15:1031. [PMID: 39202391 PMCID: PMC11353499 DOI: 10.3390/genes15081031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Revised: 07/30/2024] [Accepted: 08/02/2024] [Indexed: 09/03/2024] Open
Abstract
Tubulinopathies are associated with malformations of cortical development but not Walker-Warburg Syndrome. Intensive monitoring of a Croatian infant presenting as Walker-Warburg Syndrome in utero began at 21 weeks due to increased growth of cerebral ventricles and foetal biparietal diameter. Monitoring continued until Caesarean delivery at 34 weeks where the infant was eutrophic. Clinical assessment of a progressive neurological disorder of unknown aetiology found a macrocephalic head and markedly hypoplastic genitalia with a micropenis. Neurological examination showed generalized hypotonia with very rare spontaneous movements, hypotonia-induced respiratory insufficiency and ventilator dependence, and generalized myoclonus intensifying during manipulation. With clinical features of hypotonia, lissencephaly, and brain malformations, Walker-Warburg Syndrome was suspected; however, eye anomalies were absent. Genetic trio analysis via whole-exome sequencing only identified a novel de novo mutation in the TUBA1A gene (NM_006009.4:c.848A>G; NP_006000.2:p.His283Arg) in the infant, who died at 2 months of age, as the likely cause. We report a previously unpublished, very rare heterozygous TUBA1A mutation with clinical features of macrocephaly and hypoplastic genitalia which have not previously been associated with the gene. The absence of eye phenotypes or mutations in Walker-Warburg-associated genes confirm this as not a new presentation of Walker-Warburg Syndrome but a novel TUBA1A tubulinopathy for neonatologists to be aware of.
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Affiliation(s)
- Akzam Saidin
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia; (A.S.); (Z.S.); (R.H.); (M.G.R.)
- Novocraft Technologies, Petaling Jaya 46300, Malaysia
| | - Anet Papazovska Cherepnalkovski
- Department of Neonatology, Clinic for Gynecology and Obstetrics, Clinical Hospital Center Split, 21000 Split, Croatia; (A.P.C.); (M.B.); (K.C.)
- Department of Health Studies, University of Split, 21000 Split, Croatia
| | - Zeeshan Shaukat
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia; (A.S.); (Z.S.); (R.H.); (M.G.R.)
| | - Todor Arsov
- Faculty of Medical Sciences, University Goce Delcev in Shtip, 2000 Shtip, North Macedonia;
| | - Rashid Hussain
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia; (A.S.); (Z.S.); (R.H.); (M.G.R.)
| | - Ben J. Roberts
- Clinical and Health Sciences, Health and Biomedical Innovation, University of South Australia, Adelaide, SA 5000, Australia;
| | - Marija Bucat
- Department of Neonatology, Clinic for Gynecology and Obstetrics, Clinical Hospital Center Split, 21000 Split, Croatia; (A.P.C.); (M.B.); (K.C.)
| | - Klara Cogelja
- Department of Neonatology, Clinic for Gynecology and Obstetrics, Clinical Hospital Center Split, 21000 Split, Croatia; (A.P.C.); (M.B.); (K.C.)
| | - Michael G. Ricos
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia; (A.S.); (Z.S.); (R.H.); (M.G.R.)
| | - Leanne M. Dibbens
- Epilepsy Research Group, Clinical and Health Sciences, Australian Centre for Precision Health, University of South Australia, Adelaide, SA 5000, Australia; (A.S.); (Z.S.); (R.H.); (M.G.R.)
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Xu K, Li Z, Mao L, Guo Z, Chen Z, Chai Y, Xie C, Yang X, Na J, Li W, Ou G. AlphaFold2-guided engineering of split-GFP technology enables labeling of endogenous tubulins across species while preserving function. PLoS Biol 2024; 22:e3002615. [PMID: 39159282 PMCID: PMC11361732 DOI: 10.1371/journal.pbio.3002615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 08/29/2024] [Accepted: 07/29/2024] [Indexed: 08/21/2024] Open
Abstract
Dynamic properties are essential for microtubule (MT) physiology. Current techniques for in vivo imaging of MTs present intrinsic limitations in elucidating the isotype-specific nuances of tubulins, which contribute to their versatile functions. Harnessing the power of the AlphaFold2 pipeline, we engineered a strategy for the minimally invasive fluorescence labeling of endogenous tubulin isotypes or those harboring missense mutations. We demonstrated that a specifically designed 16-amino acid linker, coupled with sfGFP11 from the split-sfGFP system and integration into the H1-S2 loop of tubulin, facilitated tubulin labeling without compromising MT dynamics, embryonic development, or ciliogenesis in Caenorhabditis elegans. Extending this technique to human cells and murine oocytes, we visualized MTs with the minimal background fluorescence and a pathogenic tubulin isoform with fidelity. The utility of our approach across biological contexts and species set an additional paradigm for studying tubulin dynamics and functional specificity, with implications for understanding tubulin-related diseases known as tubulinopathies.
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Affiliation(s)
- Kaiming Xu
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, McGovern Institute for Brain Research, State Key Laboratory of Membrane Biology, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Zhiyuan Li
- School of Life Sciences, MOE Key Laboratory of Bioinformatics, Center for Synthetic & Systems Biology, Tsinghua University, Beijing, China
| | - Linfan Mao
- School of Medicine, Tsinghua University, Beijing, China
| | - Zhengyang Guo
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, McGovern Institute for Brain Research, State Key Laboratory of Membrane Biology, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Zhe Chen
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, McGovern Institute for Brain Research, State Key Laboratory of Membrane Biology, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Yongping Chai
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, McGovern Institute for Brain Research, State Key Laboratory of Membrane Biology, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Chao Xie
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, McGovern Institute for Brain Research, State Key Laboratory of Membrane Biology, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
| | - Xuerui Yang
- School of Life Sciences, MOE Key Laboratory of Bioinformatics, Center for Synthetic & Systems Biology, Tsinghua University, Beijing, China
| | - Jie Na
- School of Medicine, Tsinghua University, Beijing, China
| | - Wei Li
- School of Medicine, Tsinghua University, Beijing, China
| | - Guangshuo Ou
- Tsinghua-Peking Center for Life Sciences, Beijing Frontier Research Center for Biological Structure, McGovern Institute for Brain Research, State Key Laboratory of Membrane Biology, School of Life Sciences and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China
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3
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Liang X, Gong M, Wang Z, Wang J, Guo W, Cai A, Yang Z, Liu X, Xu F, Xiong W, Fu C, Wang X. LncRNA TubAR complexes with TUBB4A and TUBA1A to promote microtubule assembly and maintain myelination. Cell Discov 2024; 10:54. [PMID: 38769343 PMCID: PMC11106304 DOI: 10.1038/s41421-024-00667-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 03/13/2024] [Indexed: 05/22/2024] Open
Abstract
A long-standing hypothesis proposes that certain RNA(s) must exhibit structural roles in microtubule assembly. Here, we identify a long noncoding RNA (TubAR) that is highly expressed in cerebellum and forms RNA-protein complex with TUBB4A and TUBA1A, two tubulins clinically linked to cerebellar and myelination defects. TubAR knockdown in mouse cerebellum causes loss of oligodendrocytes and Purkinje cells, demyelination, and decreased locomotor activity. Biochemically, we establish the roles of TubAR in promoting TUBB4A-TUBA1A heterodimer formation and microtubule assembly. Intriguingly, different from the hypomyelination-causing mutations, the non-hypomyelination-causing mutation TUBB4A-R2G confers gain-of-function for an RNA-independent interaction with TUBA1A. Experimental use of R2G/A mutations restores TUBB4A-TUBA1A heterodimer formation, and rescues the neuronal cell death phenotype caused by TubAR knockdown. Together, we uncover TubAR as the long-elusive structural RNA for microtubule assembly and demonstrate how TubAR mediates microtubule assembly specifically from αβ-tubulin heterodimers, which is crucial for maintenance of cerebellar myelination and activity.
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Affiliation(s)
- Xiaolin Liang
- Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Meng Gong
- Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Zhikai Wang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Jie Wang
- Songjiang Hospital and Songjiang Research Institute, Shanghai Key Laboratory of Emotions and Affective Disorders, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Neuroscience and Brain Diseases, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, China
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Weiwei Guo
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Aoling Cai
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Zhenye Yang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Xing Liu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China
| | - Fuqiang Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Wei Xiong
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China.
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
| | - Chuanhai Fu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China.
| | - Xiangting Wang
- Department of Geriatrics, Gerontology Institute of Anhui Province, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China.
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, School of Life Sciences/Division of Biomedical Sciences, Hefei, Anhui, China.
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Dheer A, Bosco DB, Zheng J, Wang L, Zhao S, Haruwaka K, Yi MH, Barath A, Tian DS, Wu LJ. Chemogenetic approaches reveal dual functions of microglia in seizures. Brain Behav Immun 2024; 115:406-418. [PMID: 37926132 PMCID: PMC10841657 DOI: 10.1016/j.bbi.2023.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/14/2023] [Accepted: 11/02/2023] [Indexed: 11/07/2023] Open
Abstract
Microglia are key players in maintaining brain homeostasis and exhibit phenotypic alterations in response to epileptic stimuli. However, it is still relatively unknown if these alterations are pro- or anti-epileptic. To unravel this dilemma, we employed chemogenetic manipulation of microglia using the artificial Gi-Dreadd receptor within a kainic acid (KA) induced murine seizure model. Our results indicate that acute Gi-Dreadd activation with Clozapine-N-Oxide can reduce seizure severity. Additionally, we observed increased interaction between microglia and neuronal soma, which correlated with reduced neuronal hyperactivity. Interestingly, prolonged activation of microglial Gi-Dreadds by repeated doses of CNO over 3 days, arrested microglia in a less active, homeostatic-like state, which associated with increased neuronal loss after KA induced seizures. RNAseq analysis revealed that prolonged activation of Gi-Dreadd interferes with interferon β signaling and microglia proliferation. Thus, our findings highlight the importance of microglial Gi signaling not only during status epilepticus (SE) but also within later seizure induced pathology.
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Affiliation(s)
- Aastha Dheer
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Dale B Bosco
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Lingxiao Wang
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | | | - Min-Hee Yi
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Abhijeet Barath
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Dai-Shi Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Department of Immunology, Mayo Clinic, Rochester, MN, USA.
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Wen J, Wang Q, Zhang W, Wang W. TUBA1A licenses APC/C-mediated mitotic progression to drive glioblastoma growth by inhibiting PLK3. FEBS Lett 2023; 597:3072-3086. [PMID: 37873730 DOI: 10.1002/1873-3468.14764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/05/2023] [Indexed: 10/25/2023]
Abstract
Glioblastoma (GBM) is the most common, aggressive, and chemorefractory primary brain tumor in adults. Identifying novel drug targets is crucial for GBM treatment. Here, we demonstrate that tubulin alpha 1a (TUBA1A) is significantly upregulated in GBM compared to low-grade gliomas (LGG) and normal tissues. High TUBA1A expression is associated with poor survival in GBM patients. TUBA1A knockdown results in mitotic arrest and reduces tumor growth in mice. TUBA1A interacts with the polo-like kinase 3 (PLK3) in the cytoplasm to inhibit its activation. This interaction licenses activation of the anaphase-promoting complex or cyclosome (APC/C) to ensure proper Foxm1-mediated metaphase-to-anaphase transition and mitotic exit. Overall, our findings demonstrate that targeting TUBA1A attenuates GBM cell growth by suppressing mitotic progression in a PLK3-dependent manner.
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Affiliation(s)
- Jiaqi Wen
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Guangdong Pharmaceutical University, Guangzhou, China
- Guangdong Key Laboratory of Bioactive Drug Research, Guangzhou, China
| | - Qiuke Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Guangdong Pharmaceutical University, Guangzhou, China
- Guangdong Key Laboratory of Bioactive Drug Research, Guangzhou, China
| | - Wenyi Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Guangdong Pharmaceutical University, Guangzhou, China
- Guangdong Key Laboratory of Bioactive Drug Research, Guangzhou, China
| | - Weizhang Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Guangdong Pharmaceutical University, Guangzhou, China
- Guangdong Key Laboratory of Bioactive Drug Research, Guangzhou, China
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Ramesh Babu PB. Prediction of anti-microtubular target proteins of tubulins and their interacting proteins using Gene Ontology tools. J Genet Eng Biotechnol 2023; 21:78. [PMID: 37466845 DOI: 10.1186/s43141-023-00531-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 07/01/2023] [Indexed: 07/20/2023]
Abstract
BACKGROUND Tubulins are highly conserved globular proteins involved in stabilization of cellular cytoskeletal microtubules during cell cycle. Different isoforms of tubulins are differentially expressed in various cell types, and their protein-protein interactions (PPIs) analysis will help in identifying the anti-microtubular drug targets for cancer and neurological disorders. Numerous web-based PPIs analysis methods are recently being used, and in this paper, I used Gene Ontology (GO) tools, e.g., Stringbase, ProteomeHD, GeneMANIA, and ShinyGO, to identify anti-microtubular target proteins by selecting strongly interacting proteins of tubulins. RESULTS I used 6 different human tubulin isoforms (two from each of α-, β-, and γ-tubulin) and found several thousands of node-to-node protein interactions (highest 4956 in GeneMANIA) and selected top 10 strongly interacting node-to-node interactions with highest score, which included 7 tubulin family protein and 6 non-tubulin family proteins (total 13). Functional enrichment analysis indicated a significant role of these 13 proteins in nucleation, polymerization or depolymerization of microtubules, membrane tethering and docking, dorsal root ganglion development, mitotic cycle, and cytoskeletal organization. I found γ-tubulins (TUBG1, TUBGCP4, and TUBBGCP6) were known to contribute majorly for tubulin-associated functions followed by α-tubulin (TUBA1A) and β-tubulins (TUBB AND TUBB3). In PPI results, I found several non-tubular proteins interacting with tubulins, and six of them (HTT, DPYSL2, SKI, UNC5C, NINL, and DDX41) were found closely associated with their functions. CONCLUSIONS Increasing number of regulatory proteins and subpopulation of tubulin proteins are being reported with poor understanding in their association with microtubule assembly and disassembly. The functional enrichment analysis of tubulin isoforms using recent GO tools resulted in identification of γ-tubulins playing a key role in microtubule functions and observed non-tubulin family of proteins HTT, DPYSL2, SKI, UNC5C, NINL, and DDX41 strongly interacting functional proteins of tubulins. The present study yields a promising model system using GO tools to narrow down tubulin-associated proteins as a drug target in cancer, Alzheimer's, neurological disorders, etc.
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Affiliation(s)
- Polani B Ramesh Babu
- Center for Materials Engineering and Regenerative Medicine, Bharath Institute of Higher Education and Research, Bharath Institute of Science and Technology, Selaiyur, Tambaram, Chennai, India.
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Zocchi R, Bellacchio E, Piccione M, Scardigli R, D’Oria V, Petrini S, Baranano K, Bertini E, Sferra A. Novel loss of function mutation in TUBA1A gene compromises tubulin stability and proteostasis causing spastic paraplegia and ataxia. Front Cell Neurosci 2023; 17:1162363. [PMID: 37435044 PMCID: PMC10332271 DOI: 10.3389/fncel.2023.1162363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/01/2023] [Indexed: 07/13/2023] Open
Abstract
Microtubules are dynamic cytoskeletal structures involved in several cellular functions, such as intracellular trafficking, cell division and motility. More than other cell types, neurons rely on the proper functioning of microtubules to conduct their activities and achieve complex morphologies. Pathogenic variants in genes encoding for α and β-tubulins, the structural subunits of microtubules, give rise to a wide class of neurological disorders collectively known as "tubulinopathies" and mainly involving a wide and overlapping range of brain malformations resulting from defective neuronal proliferation, migration, differentiation and axon guidance. Although tubulin mutations have been classically linked to neurodevelopmental defects, growing evidence demonstrates that perturbations of tubulin functions and activities may also drive neurodegeneration. In this study, we causally link the previously unreported missense mutation p.I384N in TUBA1A, one of the neuron-specific α-tubulin isotype I, to a neurodegenerative disorder characterized by progressive spastic paraplegia and ataxia. We demonstrate that, in contrast to the p.R402H substitution, which is one of the most recurrent TUBA1A pathogenic variants associated to lissencephaly, the present mutation impairs TUBA1A stability, reducing the abundance of TUBA1A available in the cell and preventing its incorporation into microtubules. We also show that the isoleucine at position 384 is an amino acid residue, which is critical for α-tubulin stability, since the introduction of the p.I384N substitution in three different tubulin paralogs reduces their protein level and assembly into microtubules, increasing their propensity to aggregation. Moreover, we demonstrate that the inhibition of the proteasome degradative systems increases the protein levels of TUBA1A mutant, promoting the formation of tubulin aggregates that, as their size increases, coalesce into inclusions that precipitate within the insoluble cellular fraction. Overall, our data describe a novel pathogenic effect of p.I384N mutation that differs from the previously described substitutions in TUBA1A, and expand both phenotypic and mutational spectrum related to this gene.
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Affiliation(s)
- Riccardo Zocchi
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Emanuele Bellacchio
- Molecular Genetics and Functional Genomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Michela Piccione
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy
| | - Raffaella Scardigli
- Consiglio Nazionale delle Ricerche (CNR), Institute of Translational Pharmacology (IFT), Rome, Italy
- European Brain Research Institute (EBRI) “Rita Levi-Montalcini,” Rome, Italy
| | - Valentina D’Oria
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy
| | - Stefania Petrini
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy
| | - Kristin Baranano
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Enrico Bertini
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Antonella Sferra
- Unit of Neuromuscular Disorders, Translational Pediatrics and Clinical Genetics, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
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Hoff KJ, Neumann AJ, Moore JK. The molecular biology of tubulinopathies: Understanding the impact of variants on tubulin structure and microtubule regulation. Front Cell Neurosci 2022; 16:1023267. [PMID: 36406756 PMCID: PMC9666403 DOI: 10.3389/fncel.2022.1023267] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/30/2022] [Indexed: 11/24/2022] Open
Abstract
Heterozygous, missense mutations in both α- and β-tubulin genes have been linked to an array of neurodevelopment disorders, commonly referred to as "tubulinopathies." To date, tubulinopathy mutations have been identified in three β-tubulin isotypes and one α-tubulin isotype. These mutations occur throughout the different genetic domains and protein structures of these tubulin isotypes, and the field is working to address how this molecular-level diversity results in different cellular and tissue-level pathologies. Studies from many groups have focused on elucidating the consequences of individual mutations; however, the field lacks comprehensive models for the molecular etiology of different types of tubulinopathies, presenting a major gap in diagnosis and treatment. This review highlights recent advances in understanding tubulin structural dynamics, the roles microtubule-associated proteins (MAPs) play in microtubule regulation, and how these are inextricably linked. We emphasize the value of investigating interactions between tubulin structures, microtubules, and MAPs to understand and predict the impact of tubulinopathy mutations at the cell and tissue levels. Microtubule regulation is multifaceted and provides a complex set of controls for generating a functional cytoskeleton at the right place and right time during neurodevelopment. Understanding how tubulinopathy mutations disrupt distinct subsets of those controls, and how that ultimately disrupts neurodevelopment, will be important for establishing mechanistic themes among tubulinopathies that may lead to insights in other neurodevelopment disorders and normal neurodevelopment.
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Affiliation(s)
| | | | - Jeffrey K. Moore
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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Pediatric Brain Maturation and Migration Disorders. Diagnostics (Basel) 2022; 12:diagnostics12051123. [PMID: 35626279 PMCID: PMC9139849 DOI: 10.3390/diagnostics12051123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/13/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022] Open
Abstract
Neurodevelopmental disorders, including neuronal migration disorders, are best understood in the context of altered normal development. Neurons normally migrate from their site of origin to their (usually cortical) destination using a wide range of molecular and cellular signaling as a guide. In the case of abnormal migration neurons: (1) do not migrate and remain at their site of origin; (2) incompletely migrate and remain within the white matter; (3) migrate to the cortex but fail to organize correctly; or (4) over-migrate, beyond the cortex. In this review, we discuss normal brain development, along with the malformations that result from these different migration abnormalities.
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