Regulation of Dendritic Morphogenesis by Rho GTPases

Dendritic morphogenesis, the process by which neurons elaborate their branching patterns and spine structures, is critically governed by the Rho family of small GTPases. RhoA, Rac1 and Cdc42 function as molecular switches that transduce extracellular cues into precise remodelling of the actin cytoskeleton, thereby determining dendrite extension, branching complexity and spine formation. Activation of these GTPases is mediated by guanine nucleotide exchange factors (GEFs), while GTPase-activating proteins (GAPs) ensure timely inactivation. Through finely balanced interplay between RhoA-driven contractility and Rac1/Cdc42-driven protrusive dynamics, neurons establish appropriate dendritic arbors essential for synaptic connectivity and information processing. Dysregulation of these pathways underlies a spectrum of neurodevelopmental and neuropsychiatric disorders, emphasising the importance of understanding both the molecular architecture of Rho GTPase regulators and their signalling networks. Recent advances have revealed novel lipid-binding modes, domain-specific control of GTPase activity and mechanistic links between genetic variants and morphological phenotypes, offering fresh insights into both fundamental neuroscience and potential therapeutic strategies.

Research from Nature Portfolio

High-resolution studies have elucidated how the Sec14 domain of the RhoGEF Kalirin adopts a closed conformation that selectively binds lysophospholipids via a surface groove, coupling membrane lipid sensing to Rac1-mediated actin remodelling and spine maintenance. Structural and biochemical characterisation of this domain has provided a model for how lipid interactions fine-tune GEF activity and, consequently, dendritic spine architecture. Complementing this, analyses of de novo mutations in the GEF1 domain of the RhoGEF Trio have uncovered a hotspot whose variants produce either hyperfunctional or hypofunctional forms of Trio. These opposite perturbations of Rac1 activation were shown to alter dendritic spine density and synaptic AMPA-receptor expression, thereby linking domain-specific GEF activity to neurodevelopmental phenotypes.

Regulation of Dendritic Morphogenesis by Rho GTPases publication trend

The graph below shows the total number of articles in regulation of dendritic morphogenesis by rho gtpases across all publications each year (not limited to Nature Index journals).

Technical terms

Dendritic morphogenesis: The development and shaping of dendritic arbors and spines in neurons.

Rho GTPase: A family of small guanosine triphosphatases that regulate cytoskeletal dynamics by cycling between active (GTP-bound) and inactive (GDP-bound) states.

Guanine nucleotide exchange factor (GEF): A protein that catalyses the exchange of GDP for GTP on GTPases, thereby activating them.

Actin cytoskeleton: A network of filamentous proteins within cells that provides structural support and drives morphological changes.

Dendritic spine: A small, actin-rich protrusion on a dendrite that forms the postsynaptic compartment of most excitatory synapses.

References

1. Structure of the Sec14 domain of Kalirin reveals a distinct class of lipid-binding module in RhoGEFs. Nature Communications (2023).
2. An autism spectrum disorder-related de novo mutation hotspot discovered in the GEF1 domain of Trio. Nature Communications (2017).
3. Control of Dendritic Spine Morphological and Functional Plasticity by Small GTPases. Neural Plasticity (2016).
4. Loss of Cdc42 leads to defects in synaptic plasticity and remote memory recall. eLife (2014).
5. The RhoGEF Trio Functions in Sculpting Class Specific Dendrite Morphogenesis in Drosophila Sensory Neurons. PLOS ONE (2012).