Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations

Mutations in the family of genes encoding the tubulin subunits of microtubules are associated with a spectrum of human brain malformations known as tubulinopathies. How these mutations impact tubulin activity to give rise to distinct developmental consequences is poorly understood. Here we report tw...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Kristen Park, Katelyn J. Hoff, Linnea Wethekam, Nicholas Stence, Margarita Saenz, Jeffrey K. Moore
Formato:	article
Lenguaje:	EN
Publicado:	Frontiers Media S.A. 2021
Materias:	cytoskeleton microtubule tubulin tubulinopathy brain development Biology (General) QH301-705.5
Acceso en línea:	https://doaj.org/article/ac8d754a64604c65ac813b97bc4abbe2
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:ac8d754a64604c65ac813b97bc4abbe2
record_format	dspace
spelling	oai:doaj.org-article:ac8d754a64604c65ac813b97bc4abbe22021-11-18T09:36:17ZKinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations2296-634X10.3389/fcell.2021.765992https://doaj.org/article/ac8d754a64604c65ac813b97bc4abbe22021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/fcell.2021.765992/fullhttps://doaj.org/toc/2296-634XMutations in the family of genes encoding the tubulin subunits of microtubules are associated with a spectrum of human brain malformations known as tubulinopathies. How these mutations impact tubulin activity to give rise to distinct developmental consequences is poorly understood. Here we report two patients exhibiting brain malformations characteristic of tubulinopathies and heterozygous T178M missense mutations in different β-tubulin genes, TUBB2A or TUBB3. RNAseq analysis indicates that both TUBB2A and TUBB3 are expressed in the brain during development, but only TUBB2A maintains high expression in neurons into adulthood. The T178 residue is highly conserved in β-tubulins and located in the exchangeable GTP-binding pocket of β-tubulin. To determine the impact of T178M on β-tubulin function we created an analogous mutation in the β-tubulin of budding yeast and show that the substitution acts dominantly to produce kinetically stabilized microtubules that assemble and disassemble slowly, with fewer transitions between these states. In vitro experiments with purified mutant tubulin demonstrate that T178M decreases the intrinsic assembly activity of β-tubulin and forms microtubules that rarely transition to disassembly. We provide evidence that the T178M substitution disrupts GTPase-dependent conformational changes in tubulin, providing a mechanistic explanation for kinetic stabilization. Our findings demonstrate the importance of tubulin’s GTPase activity during brain development, and indicate that tubulin isotypes play different, important roles during brain development.Kristen ParkKatelyn J. HoffLinnea WethekamNicholas StenceMargarita SaenzJeffrey K. MooreFrontiers Media S.A.articlecytoskeletonmicrotubuletubulintubulinopathybrain developmentBiology (General)QH301-705.5ENFrontiers in Cell and Developmental Biology, Vol 9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cytoskeleton microtubule tubulin tubulinopathy brain development Biology (General) QH301-705.5
spellingShingle	cytoskeleton microtubule tubulin tubulinopathy brain development Biology (General) QH301-705.5 Kristen Park Katelyn J. Hoff Linnea Wethekam Nicholas Stence Margarita Saenz Jeffrey K. Moore Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations
description	Mutations in the family of genes encoding the tubulin subunits of microtubules are associated with a spectrum of human brain malformations known as tubulinopathies. How these mutations impact tubulin activity to give rise to distinct developmental consequences is poorly understood. Here we report two patients exhibiting brain malformations characteristic of tubulinopathies and heterozygous T178M missense mutations in different β-tubulin genes, TUBB2A or TUBB3. RNAseq analysis indicates that both TUBB2A and TUBB3 are expressed in the brain during development, but only TUBB2A maintains high expression in neurons into adulthood. The T178 residue is highly conserved in β-tubulins and located in the exchangeable GTP-binding pocket of β-tubulin. To determine the impact of T178M on β-tubulin function we created an analogous mutation in the β-tubulin of budding yeast and show that the substitution acts dominantly to produce kinetically stabilized microtubules that assemble and disassemble slowly, with fewer transitions between these states. In vitro experiments with purified mutant tubulin demonstrate that T178M decreases the intrinsic assembly activity of β-tubulin and forms microtubules that rarely transition to disassembly. We provide evidence that the T178M substitution disrupts GTPase-dependent conformational changes in tubulin, providing a mechanistic explanation for kinetic stabilization. Our findings demonstrate the importance of tubulin’s GTPase activity during brain development, and indicate that tubulin isotypes play different, important roles during brain development.
format	article
author	Kristen Park Katelyn J. Hoff Linnea Wethekam Nicholas Stence Margarita Saenz Jeffrey K. Moore
author_facet	Kristen Park Katelyn J. Hoff Linnea Wethekam Nicholas Stence Margarita Saenz Jeffrey K. Moore
author_sort	Kristen Park
title	Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations
title_short	Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations
title_full	Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations
title_fullStr	Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations
title_full_unstemmed	Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations
title_sort	kinetically stabilizing mutations in beta tubulins create isotype-specific brain malformations
publisher	Frontiers Media S.A.
publishDate	2021
url	https://doaj.org/article/ac8d754a64604c65ac813b97bc4abbe2
work_keys_str_mv	AT kristenpark kineticallystabilizingmutationsinbetatubulinscreateisotypespecificbrainmalformations AT katelynjhoff kineticallystabilizingmutationsinbetatubulinscreateisotypespecificbrainmalformations AT linneawethekam kineticallystabilizingmutationsinbetatubulinscreateisotypespecificbrainmalformations AT nicholasstence kineticallystabilizingmutationsinbetatubulinscreateisotypespecificbrainmalformations AT margaritasaenz kineticallystabilizingmutationsinbetatubulinscreateisotypespecificbrainmalformations AT jeffreykmoore kineticallystabilizingmutationsinbetatubulinscreateisotypespecificbrainmalformations
_version_	1718420921497157632

Kinetically Stabilizing Mutations in Beta Tubulins Create Isotype-Specific Brain Malformations

Ejemplares similares