RSRC2 is a novel RNA-binding protein that safeguards mitotic fidelity by interacting with the lncRNA <i>C1QTNF1-AS1</i>

Mitotic fidelity requires proper chromosome alignment at the spindle equator, a process known as chromosome congression, mediated by well-established protein networks. Although RNA-binding proteins (RBPs) and non-coding RNAs (ncRNAs) have been implicated in cell division, their functional interplay remains unclear. Here, we show that RSRC2, a poorly characterized RBP, is essential for proper cell division through its interaction with the long ncRNA C1QTNF1-AS1. Loss of either RSRC2 or C1QTNF1-AS1 causes mitotic defects. RSRC2 associates with distinct protein sets involved in splicing and centrosome biogenesis, regulating mitotic gene splicing and maintaining centriole integrity. RSRC2 depletion impairs recruitment of the centrosomal scaffold proteins PCNT and CDK5RAP2, which are essential for organizing microtubules to form the mitotic spindle. While C1QTNF1-AS1 loss does not alter RSRC2 expression or its global interactome, it reduces RSRC2 localization at the centrosome. We also find that C1QTNF1-AS1 directs RSRC2 to the centrosome, where RSRC2, in turn, promotes the recruitment of PCNT mRNA to the centrosome. Our study highlights the critical role of RNA-protein complexes in ensuring error-free mitosis and identifies RSRC2 as a multifunctional protein with dual roles in splicing and centrosome-associated RNA localization.