RESUMO
Human mutations in KATNB1 (p80) cause severe congenital cortical malformations, which encompass the clinical features of both microcephaly and lissencephaly. Although p80 plays critical roles during brain development, the underlying mechanisms remain predominately unknown. Here, we demonstrate that p80 regulates microtubule (MT) remodeling in combination with NuMA (nuclear mitotic apparatus protein) and cytoplasmic dynein. We show that p80 shuttles between the nucleus and spindle pole in synchrony with the cell cycle. Interestingly, this striking feature is shared with NuMA. Importantly, p80 is essential for aster formation and maintenance in vitro. siRNA-mediated depletion of p80 and/or NuMA induced abnormal mitotic phenotypes in cultured mouse embryonic fibroblasts and aberrant neurogenesis and neuronal migration in the mouse embryonic brain. Importantly, these results were confirmed in p80-mutant harboring patient-derived induced pluripotent stem cells and brain organoids. Taken together, our findings provide valuable insights into the pathogenesis of severe microlissencephaly, in which p80 and NuMA delineate a common pathway for neurogenesis and neuronal migration via MT organization at the centrosome/spindle pole.
Assuntos
Adenosina Trifosfatases/metabolismo , Fibroblastos/fisiologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Katanina/metabolismo , Microtúbulos/metabolismo , Malformações do Sistema Nervoso/metabolismo , Neurônios/fisiologia , Proteínas Nucleares/metabolismo , Adenosina Trifosfatases/genética , Animais , Proteínas de Ciclo Celular , Dineínas/metabolismo , Células HeLa , Humanos , Katanina/genética , Camundongos , Camundongos Endogâmicos , Mitose/genética , Mutação/genética , Malformações do Sistema Nervoso/genética , Neurogênese/genética , Proteínas Nucleares/genética , RNA Interferente Pequeno/genéticaRESUMO
Disrupted-in-schizophrenia 1 (DISC1) is a susceptibility gene for major psychiatric disorders, including schizophrenia. DISC1 has been implicated in neurodevelopment in relation to scaffolding signal complexes. Here we used proteomic analysis to screen for DISC1 interactors and identified several RNA-binding proteins, such as hematopoietic zinc finger (HZF), that act as components of RNA-transporting granules. HZF participates in the mRNA localization of inositol-1,4,5-trisphosphate receptor type 1 (ITPR1), which plays a key role in synaptic plasticity. DISC1 colocalizes with HZF and ITPR1 mRNA in hippocampal dendrites and directly associates with neuronal mRNAs, including ITPR1 mRNA. The binding potential of DISC1 for ITPR1 mRNA is facilitated by HZF. Studies of Disc1-knockout mice have revealed that DISC1 regulates the dendritic transport of Itpr1 mRNA by directly interacting with its mRNA. The DISC1-mediated mRNA regulation is involved in synaptic plasticity. We show that DISC1 binds ITPR1 mRNA with HZF, thereby regulating its dendritic transport for synaptic plasticity.
Assuntos
Hipocampo/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/genética , Proteínas do Tecido Nervoso/fisiologia , Plasticidade Neuronal/fisiologia , Proteínas/fisiologia , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/fisiologia , Regiões 3' não Traduzidas/genética , Animais , Transporte Biológico , Grânulos Citoplasmáticos/metabolismo , Dendritos/metabolismo , Dendritos/ultraestrutura , Hipocampo/citologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/deficiência , Proteínas do Tecido Nervoso/genética , Plasticidade Neuronal/genética , Ligação Proteica , Mapeamento de Interação de Proteínas , Interferência de RNA , Proteínas de Ligação a RNA/genética , Proteínas Recombinantes de Fusão/metabolismoRESUMO
Disrupted-In-Schizophrenia 1 (DISC1) is a candidate gene for susceptibility to schizophrenia. DISC1 is reported to interact with NudE-like (NUDEL), which forms a complex with lissencephaly-1 (LIS1) and 14-3-3epsilon. 14-3-3epsilon is involved in the proper localization of NUDEL and LIS1 in axons. Although the functional significance of this complex in neuronal development has been reported, the transport mechanism of the complex into axons and their functions in axon formation remain essentially unknown. Here we report that Kinesin-1, a motor protein of anterograde axonal transport, was identified as a novel DISC1-interacting molecule. DISC1 directly interacted with kinesin heavy chain of Kinesin-1. Kinesin-1 interacted with the NUDEL/LIS1/14-3-3epsilon complex through DISC1, and these molecules localized mainly at cell bodies and partially in the distal part of the axons. DISC1 partially colocalized with Kinesin family member 5A, NUDEL, LIS1, and 14-3-3epsilon in the growth cones. The knockdown of DISC1 by RNA interference or the dominant-negative form of DISC1 inhibited the accumulation of NUDEL, LIS1, and 14-3-3epsilon at the axons and axon elongation. The knockdown or the dominant-negative form of Kinesin-1 inhibited the accumulation of DISC1 at the axons and axon elongation. Furthermore, the knockdown of NUDEL or LIS1 inhibited axon elongation. Together, these results indicate that DISC1 regulates the localization of NUDEL/LIS1/14-3-3epsilon complex into the axons as a cargo receptor for axon elongation.