👤 Federico Dajas-Bailador

Neuritin 1 (NRN1) has emerged as a multifaceted regulator of synaptic plasticity, neuronal excitability and structural remodelling. This review synthesises knowledge of NRN1 function across the central and peripheral nervous systems, with a focus on its roles in sensory neurones and neuronal repair following injury. We discuss evidence that NRN1 interacts with classical neurotrophic pathways, including brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), while engaging distinct cellular mechanisms that span activity-dependent trafficking, modulation of calcium and potassium channel function and regulated local axonal mRNA translation. Accumulating data indicate that NRN1 contributes to injury-induced plasticity and functional recovery through both cell-autonomous neuronal mechanisms and non-cell-autonomous signalling involving glial and stromal cells. In long-projecting sensory axons, regulated transport and local translation of Nrn1 mRNA position NRN1 as a spatially restricted effector of axonal growth, excitability and regeneration. Dysregulation of NRN1 expression and signalling has been implicated in pathological contexts including neurodegeneration, diabetic peripheral neuropathy and inflammatory pain, where restoration of NRN1 activity promotes axonal integrity, Schwann cell survival and neurotrophic support. Beyond neurons, NRN1 also modulates inflammatory and angiogenic pathways, including VEGF and CXCR4 signalling, linking neuronal plasticity to broader tissue and immune responses. Together, these findings support a model in which NRN1 acts as a molecular integrator of neurotrophic, metabolic and injury-associated signals, coordinating plasticity while also presenting potential routes to maladaptive sensitisation. We highlight key mechanistic and translational challenges that must be addressed to harness NRN1 biology therapeutically aimed at enhancing neuronal repair while limiting persistent sensory dysfunction. Show less

Spectraplakins are large actin-microtubule linker molecules implicated in various processes, including gastrulation, wound healing, skin blistering and neuronal degeneration. Expression data for the mammalian spectraplakin ACF7 and genetic analyses of the Drosophila spectraplakin Short stop (Shot) suggest an important role during neurogenesis. Using three parallel neuronal culture systems we demonstrate that, like Shot, ACF7 is essential for axon extension and describe, for the first time, their subcellular functions during axonal growth. Firstly, both ACF7 and Shot regulate the organisation of neuronal microtubules, a role dependent on both the F-actin- and microtubule-binding domains. This role in microtubule organisation is probably the key mechanism underlying the roles of Shot and ACF7 in growth cone advance. Secondly, we found a novel role for ACF7 and Shot in regulating the actin cytoskeleton through their ability to control the formation of filopodia. This function in F-actin regulation requires EF-hand motifs and interaction with the translational regulator Krasavietz/eIF5C, indicating that the underlying mechanisms are completely different from those used to control microtubules. Our data provide the basis for the first mechanistic explanation for the role of Shot and ACF7 in the developing nervous system and demonstrate their ability to coordinate the organisation of both actin and microtubule networks during axonal growth. Show less