Glucose dissociates DDX21 dimers to regulate mRNA processing and promote epidermal differentiation (ChIP-Seq)

Glucose is an important cellular energy source, however, glucose’s function as a second messenger remains relatively unexplored. Here, we find that glucose binds directly to DDX21 to regulate its function during epidermal differentiation. Specifically, glucose binds to the ATP-binding domain of DDX21 to induce a conformational change and inhibit helicase activity. Glucose binding inhibits the dimerization of DDX21 leading to re-localization from the nucleolus to the nucleoplasm and reassembly of DDX21 into larger protein complexes, increasing its association with splicing factors. This occurs during keratinocyte differentiation, where glucose accumulation is necessary, and results in DDX21 binding to RNA processing proteins and mRNA introns. Consequently, DDX21 regulates the splicing of key differentiation factors and promotes epidermal differentiation in a glucose-dependent manner. These findings reveal a novel mechanism of glucose regulation of cell signaling. Two biological replicates of primary human foreskin keratinocytes were processed for DDX21 ChIP-seq. ChIP-seq sequencing was performed on a NovaSeq 6000, PE150, with ~40 M reads for each sample.