Biology subjects

Blue, S.

Publications and source records attributed to Blue, S..

3 recordsLinked to original sources

bioRxiv2025

KIF5A binds RNA to orchestrate synaptic mRNA localization and stress granules in ALS

Neuronal health depends on the precise transport and local translation of mRNAs to maintain synaptic function across highly polarized cellular architecture. While kinesin motor proteins are known to mediate mRNA transport, the specificity and direct involvement of individual kinesins as RNA-binding proteins (RBPs) remain unclear. Here, we demonstrate that KIF5A, a neuron-specific kinesin implicated in amyotrophic lateral sclerosis (ALS), functions as an RBP. We show that KIF5A directly binds mRNAs encoding synaptic ribosomal proteins and is required for their synaptic localization and for maintaining normal synaptic composition and function. Additionally, we show ALS-linked KIF5A mutations confer gain-of-function properties, enhancing mRNA binding, increasing synaptic ribosomal protein accumulation, inducing neuronal hyperexcitability, and impairing stress responses. These findings reveal a previously unrecognized mechanism by which mutant KIF5A disrupts synaptic homeostasis. Our work positions a kinesin motor protein as an RBP with critical roles in mRNA transport, local translation, and stress response. HighlightsO_LIKIF5A interacts with mRNA encoding synaptic ribosomal proteins C_LIO_LIKIF5A is required for normal synaptic composition and function C_LIO_LIKIF5A binds to G3BP1 and G3BP1 stress granule associated proteins C_LIO_LIKIF5A mutant ALS patient-derived motor neurons have abnormal synaptic function and stress response C_LI

neuroscience↗

bioRxiv2021

Gain-of-function cardiomyopathic mutations in RBM20 rewire splicing regulation and re-distribute ribonucleoprotein aggregates within processing bodies

RNA binding motif protein 20 (RBM20) is a key regulator of alternative splicing in the heart, and its mutation leads to malignant dilated cardiomyopathy (DCM). To understand the mechanism of RBM20-associated DCM, we engineered isogenic human induced pluripotent stem cells (iPSCs) with heterozygous or homozygous DCM-associated missense mutations in RBM20 (R636S) as well as RBM20 knockout (KO) iPSCs. iPSC-derived engineered heart tissues made from these cell lines recapitulated contractile dysfunction of RBM20-associated DCM and revealed greater dysfunction with missense mutations than KO. Analysis of RBM20 RNA binding by eCLIP revealed a gain-of-function preference of mutant RBM20 for 3' UTR sequences that are shared with amyotrophic lateral sclerosis (ALS) and processing-body associated RNA binding proteins (FUS, DDX6). Deep RNA sequencing revealed that the RBM20 R636S mutant has unique gene, splicing, polyadenylation and circular RNA defects that differ from RBM20 KO, impacting distinct cardiac signaling pathways. Splicing defects specific to KO or R636S mutations were supported by data from R636S gene-edited pig hearts and eCLIP. Super-resolution microscopy verified that mutant RBM20 maintains limited nuclear localization potential; rather, the mutant protein associates with cytoplasmic processing bodies (DDX6) under basal conditions, and with stress granules (G3BP1) following acute stress. Taken together, our results highlight a novel pathogenic mechanism in cardiac disease through splicing-dependent and -independent pathways that are likely to mediate differential contractile phenotypes and stress-associated heart pathology.

cell biology↗

bioRxiv2019

The cohesin loader NIPBL interacts with pre-ribosomal RNA and treacle to regulate ribosomal RNA synthesis

NIPBL is an essential loader of cohesin to mediate sister chromatid cohesion and chromatin loop organization. NIPBL mutations cause Cornelia de Lange Syndrome. How NIPBLs genomic localization is specified is not fully understood. We found that NIPBL localizes to the nucleolus in an RNA-dependent manner and binds directly to ribosomal RNA (rRNA). We identified two RNA binding domains in NIPBL in vitro, both of which are required for efficient rRNA binding in vivo. NIPBL binds to ribosomal DNA (rDNA) in an RNA-stimulated manner, recruits PAF1 and promotes pre-rRNA transcription. Stress that inhibits rRNA synthesis displaces NIPBL from the nucleolus and rDNA. Interestingly, treacle, mutated in Treacher Collins syndrome, tightly binds to and recruits NIPBL to the nucleolus, nucleolar organizer regions, and the stress-induced nucleolar cap. The results reveal that a subpopulation of NIPBL is recruited to the nucleolus through its interaction with RNA and treacle and regulates pre-rRNA transcription.

molecular biology↗