Biology subjects

Firestein, B. L.

Publications and source records attributed to Firestein, B. L..

3 recordsLinked to original sources

bioRxiv2026

A CK2α-G3BP1 signaling axis regulates local translation in developing neurons and is disrupted in OCNDS

Neurodevelopmental disorders are frequently caused by mutations in pleiotropic kinases, yet downstream effectors driving neuronal pathology remain undefined. Here, we identify the G3BP1-dependent stress granule pathway as the dominant effector of casein kinase 2 (CK2) in developing neurons, implying that its dysregulation underlies the neurodevelopmental deficits of Okur-Chung neurodevelopmental syndrome (OCNDS). OCNDS-associated CK2 mutations reduce phosphorylation of G3BP1 at serine 149, promoting aberrant phase separation and persistent granules that sequester neuronal mRNAs and suppress local protein synthesis across axonal and dendritic compartments. These phenotypes produce allele-specific deficits in neuronal morphogenesis, synaptic abundance, and network excitability, which are conserved in a knock-in mouse model and in patient-derived iPSC neurons. G3bp1 knockdown rescues translational and morphological phenotypes across all OCNDS alleles, demonstrating that restoring granule homeostasis reverses neuronal pathology. Together, these findings establish OCNDS as a disorder of compartment-specific translational dysregulation driven by impaired CK2-G3BP1 control of RNA granule homeostasis. SummaryOCNDS mutations disrupt CK2-G3BP1 signaling, causing persistent granules and defective neuronal translation and development.

neuroscience↗

bioRxiv2024

RIPK3 promotes neuronal survival by suppressing excitatory neurotransmission during CNS viral infection

While recent work has identified roles for immune mediators in the regulation of neural activity, the capacity for cell intrinsic innate immune signaling within neurons to influence neurotransmission remains poorly understood. However, the existing evidence linking immune signaling with neuronal function suggests that modulation of neurotransmission may serve previously undefined roles in host protection during infection of the central nervous system. Here, we identify a specialized function for RIPK3, a kinase traditionally associated with necroptotic cell death, in preserving neuronal survival during neurotropic flavivirus infection through the suppression of excitatory neurotransmission. We show that RIPK3 coordinates transcriptomic changes in neurons that suppress neuronal glutamate signaling, thereby desensitizing neurons to excitotoxic cell death. These effects occur independently of the traditional functions of RIPK3 in promoting necroptosis and inflammatory transcription. Instead, RIPK3 promotes phosphorylation of the key neuronal regulatory kinase CaMKII, which in turn activates the transcription factor CREB to drive a neuroprotective transcriptional program and suppress deleterious glutamatergic signaling. These findings identify an unexpected function for a canonical cell death protein in promoting neuronal survival during viral infection through the modulation of neuronal activity, highlighting new mechanisms of neuroimmune crosstalk.

neuroscience↗

bioRxiv2020

CCP1, a tubulin deglutamylase, increases survival of rodent spinal cord neurons following glutamate-induced excitotoxicity

Microtubules (MTs) are cytoskeletal elements that provide structural support, establish morphology, and act as roadways for intracellular transport in cells. Neurons extend and must maintain long axons and dendrites to transmit information through the nervous system. Therefore, in neurons, the ability to independently regulate cytoskeletal stability and MT-based transport in different cellular compartments is essential. Post-translational modification of MTs is one mechanism by which neurons can regulate the cytoskeleton. The carboxypeptidase CCP1 negatively regulates post-translational glutamylation of MTs. We previously demonstrated that the CCP1 homolog in C. elegans is important for maintenance of cilia. In mammals, loss of CCP1, and the resulting hyperglutamylation of MTs, causes neurodegeneration. It has long been known that CCP1 expression is activated by neuronal injury; however, whether CCP1 plays a neuroprotective role after injury is unknown. Furthermore, it not yet clear whether CCP1 acts on ciliary MTs in spinal cord neurons. Using an in vitro model of excitotoxic neuronal injury coupled with shRNA-mediated knockdown of CCP1, we demonstrate that CCP1 protects neurons from excitotoxic death. Unexpectedly, excitotoxic injury reduced CCP1 expression in our system, and knockdown of CCP1 did not result in loss or shortening of cilia in cultured spinal cord neurons. Our results suggest that CCP1 acts on axonal and dendritic MTs to promote cytoskeletal rearrangements that support neuroregeneration and that enzymes responsible for glutamylation of MTs might be therapeutically targeted to prevent excitotoxic death after spinal cord injuries.

cell biology↗