Autoinhibition of the GEF activity of cytoskeletal regulatory protein Trio is disrupted in neurodevelopmental disorder-related genetic variants

Bircher, Josie; Corcoran, Ellen; Lam, TuKiet T.; Trnka, Michael J.; Koleske, Anthony J.

doi:10.1016/j.jbc.2022.102361

Cited by 8 publications

(11 citation statements)

References 48 publications

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“…Autoinhibition has been documented for GEFs and GAPs of GTPases from various families including Ras, Rho, Arf, and Rab. Allosteric occlusion of the catalytic site is the typical mechanism (16,24,(46)(47)(48)(49)(50)(51), however more complex mechanisms have been suggested (52).…”

Section: Discussionmentioning

confidence: 99%

Sec7 regulatory domains scaffold autoinhibited and active conformations

Brownfield,

Richardson,

Halaby

et al. 2023

Preprint

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The late stages of Golgi maturation involve a series of sequential trafficking events in which cargo-laden vesicles are produced and targeted to multiple distinct subcellular destinations. Each of these vesicle biogenesis events requires activation of an Arf GTPase by the Sec7/BIG guanine nucleotide exchange factor (GEF). Sec7 localization and activity is regulated by autoinhibition, positive feedback, and interaction with other GTPases. Although these mechanisms have been characterized biochemically, we lack a clear picture of how GEF localization and activity is modulated by these signals. Here we report the cryoEM structure of full-length Sec7 in its autoinhibited form, revealing the architecture of its multiple regulatory domains. We use functional experiments to determine the basis for autoinhibition and use structural predictions to produce a model for an active conformation of the GEF that is supported empirically. This study therefore elucidates the conformational transition that Sec7 undergoes to become active on the organelle membrane surface.

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Section: Discussionmentioning

confidence: 99%

Sec7 regulatory domains scaffold autoinhibited and active conformations

Brownfield,

Richardson,

Halaby

et al. 2023

Preprint

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“…WT and +/K1431M human TRIO GEF1 and Rac1 recombinant proteins were expressed and purified from bacteria as previously described (54). GEF activity was monitored by the decrease in fluorescent signal (λ excitation = 488 nm; λ emission = 535 nm) as BODIPY-FL-GDP was exchanged for GTP on Rac1 over 30 minutes, as previously described (47, 54).…”

Section: Methodsmentioning

confidence: 99%

“…Interestingly, nonsense variants spread throughout TRIO are enriched in individuals with SCZ (34, 45), whereas pathogenic missense TRIO variants in or surrounding the GEF1 domain are associated with ASD/ID (9, 32, 33). Of these, variants in GEF1 that decrease Rac1 activation are associated with milder ID and microcephaly, whereas variants in the adjacent spectrin repeat 8 domain that increase Rac1 activation are associated with a more severe ID and macrocephaly (29, 30, 46, 47). Rare missense variants in TRIO have also been observed in BPD, epilepsy, and other disorders, but studies to date are underpowered to establish a causal link with these disorders.…”

Section: Introductionmentioning

confidence: 99%

“…Given the wide spectrum of TRIO variants associated with different pathological conditions, a fundamental and unresolved question is how distinct TRIO variants differentially impact mammalian brain development. NDD-associated TRIO variants affect GEF1 and GEF2 activities, cell morphology, inhibitory neuron maturation, axon guidance, and synapse function (25–27, 29, 30, 47); however, the impact of heterozygosity for distinct TRIO variants in vivo, as found in individuals with NDDs, has been largely unexplored.…”

Section: Introductionmentioning

confidence: 99%

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Heterozygosity for neurodevelopmental disorder-associatedTRIOvariants yields distinct deficits in behavior, neuronal development, and synaptic transmission in mice

Ishchenko,

Jeng,

Feng

et al. 2024

Preprint

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Heterozygosity for rare genetic variants inTRIOis associated with neurodevelopmental disorders (NDDs) including schizophrenia (SCZ), autism spectrum disorder (ASD) and intellectual disability. TRIO uses its two guanine nucleotide exchange factor (GEF) domains to activate GTPases (GEF1: Rac1 and RhoG; GEF2: RhoA) that control neuronal migration, synapse development and function. It remains unclear whether and how discreteTRIOvariants differentially impact these neurodevelopmental events. Here, we elucidate how heterozygosity for NDD-associatedTriovariants –+/K1431M(ASD),+/K1918X(SCZ), and+/M2145T(bipolar disorder, BPD) – impact mouse behavior, brain development, and synapse structure and function. Heterozygosity for differentTriovariants impacts motor, social, and cognitive behaviors in distinct ways that align with clinical phenotypes in humans. ASD- and SCZ-linkedTriovariants differentially impact head and brain size with corresponding changes in dendritic arbors of motor cortex layer 5 pyramidal neurons (M1 L5 PNs). Although dendritic spine density and synaptic ultrastructure were only modestly altered in theTriovariant heterozygotes, we observe significant changes in synaptic function and plasticity including excitatory/inhibitory imbalance and long-term potentiation defects. We also identify distinct changes in glutamate synaptic release in+/K1431Mand+/M2145Tcortico-cortical synapses, associated with deficiencies in crucial presynaptic release regulators. WhileTRIO K1431Mhas impaired ability to promote GTP exchange on Rac1,+/K1431Mmice exhibit increased Rac1 activity, suggesting possible compensation by other GEFs. Our work reveals that discrete disease-associatedTriovariants yield overlapping but distinct NDD-associated phenotypes in mice and demonstrates, for the first time, an essential role for Trio in presynaptic glutamate release, underscoring the importance of studying the impact of variant heterozygosity in vivo.

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“…The DH domain, which has an α-helix bundle structure, contains the RhoA binding interface. Mutations in RhoGEFs have been linked to diabetes, embryonic development, and neurodevelopmental disorders, − among others. Insights into the oncogenic constitutive activity of the lymphoid blast crisis (Lbc) RhoGEF were gained by analyzing the structure and dynamics of the protein in different functional states and in comparison with a close homologue leukemia-associated RhoGEF (LARG) .…”

Section: Introductionmentioning

confidence: 99%

Allosteric Activation of RhoA Complexed with p115-RhoGEF Deciphered by Conformational Dynamics

Haspel,

Jang,

Nussinov

2024

J. Chem. Inf. Model.

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The Ras homologue family member A (RhoA) is a member of the Rho family, a subgroup of the Ras superfamily. RhoA interacts with the 115 kDa guanine nucleotide exchange factor (p115-RhoGEF), which assists in activation and binding with downstream effectors. Here, we use molecular dynamics (MD) simulations and essential dynamics analysis of the inactive RhoA− GDP and active RhoA−GTP, when bound to p115-RhoGEF to decipher the mechanism of RhoA activation at the structural level. We observe that inactive RhoA−GDP maintains its position near the catalytic site on the Dbl homology (DH) domain of p115-RhoGEF through the interaction of its Switch I region with the DH domain. We further show that the active RhoA−GTP is engaged in more interactions with the p115-RhoGEF membrane-bound Pleckstrin homology (PH) domain as compared to RhoA−GDP. We hypothesize that the role of the interactions between the active RhoA−GTP and the PH domain is to help release it from the DH domain upon activation. Our results support this premise, and our simulations uncover the beginning of this process and provide structural details. They also point to allosteric communication pathways that take part in RhoA activation to promote and strengthen the interaction between the active RhoA−GTP and the PH domain. Allosteric regulation also occurs among other members of the Rho superfamily. Collectively, we suggest that in the activation process, the role of the RhoA−GTP interaction with the PH domain is to release RhoA−GTP from the DH domain after activation, making it available to downstream effectors.

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Autoinhibition of the GEF activity of cytoskeletal regulatory protein Trio is disrupted in neurodevelopmental disorder-related genetic variants

Cited by 8 publications

References 48 publications

Sec7 regulatory domains scaffold autoinhibited and active conformations

Sec7 regulatory domains scaffold autoinhibited and active conformations

Heterozygosity for neurodevelopmental disorder-associatedTRIOvariants yields distinct deficits in behavior, neuronal development, and synaptic transmission in mice

Allosteric Activation of RhoA Complexed with p115-RhoGEF Deciphered by Conformational Dynamics

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