CREB3L1 regulates mitochondrial bioenergetics and cytoskeletal remodeling during axon specification in developing neurons

The transition from a neural progenitor to a mature, polarized neuron requires a substantial and strictly coordinated investment of cellular energy. While the genetic cascades governing cytoskeletal remodeling and structural polarity are well documented, how these programs are metabolically supported during early differentiation remains a fundamental question in neurobiology. In this study, using three different species as study models: rats, mice, and humans and an unbiased transcriptomic approach, we identify the transcription factor CREB3L1 as a key molecular regulator that dynamically modulates both neuronal morphogenesis and cellular bioenergetics. Through targeted CRISPR-Cas9 knockout in human iPSC-derived glutamatergic neurons and functional silencing in rodent models, we demonstrate that the loss of CREB3L1 disrupts critical cytoskeletal networks required for axonogenesis. This structural collapse is accompanied by a bioenergetic paradox: CREB3L1-deficient neurons trigger a compensatory upregulation of mitochondrial biogenesis programs; however, these upregulated networks are functionally defective, exhibiting dissipation of membrane potential and impaired metabolic capacity. In vivo assays using in utero electroporation reveal that this bioenergetic failure delay developing neurons in a multipolar state, thereby impairing the multipolar-to-bipolar transition relevant for proper cortical integration. Collectively, our findings define CREB3L1 as a transcriptional regulator controlling both structural architecture and mitochondrial homeostasis, offering a novel, cross-species framework for understanding neurodevelopmental vulnerabilities and neuropathologies.