PRMT1-mediated methylation controls OFIP ubiquitination and centrosome duplication to maintain epidermal homeostasis

Epidermal homeostasis relies on the precise balance between the self-renewal and differentiation of basal keratinocytes, a process highly dependent on the fidelity of cell division and centrosome function. However, the molecular mechanism regulating this process remains poorly understood. Here, we identify protein arginine methyltransferase 1 (PRMT1) as a crucial orchestrator of epidermal homeostasis. Genetic ablation of Prmt1 in mice causes severe epidermal hyperplasia characterized by aberrant expansion of the stratum basale and disruption of the mitotic fidelity of basal cells. Mechanistically, PRMT1 directly interacts with and catalyzes the asymmetric arginine dimethylation of the centrosomal OFD1/FOR20-interacting protein (OFIP) at arginine 50. This methylation is required for the subsequent recognition and ubiquitination of OFIP by the E3 ubiquitin ligase STUB1. Consequently, PRMT1 deficiency prevents OFIP methylation and degradation, resulting in its dramatic accumulation at the centrosome. This buildup drives aberrant centrosome overduplication and the formation of multipolar spindles, ultimately compromising the integrity of epidermal renewal. Our findings delineate the PRMT1-OFIP-STUB1 axis as a mechanistic framework governing centrosome numerosity and epidermal homeostasis, advancing understanding of cutaneous barrier integrity and providing a potential therapeutic target for dermatopathological conditions.