XBP1 and CREB3L Coordinate Organelle Architecture and Inter-Organelle Metabolic Flows for Mucin Production in High Endothelial and Goblet Cells

How these cells coordinate organelle architecture and biosynthetic pathways to support such demands remains poorly understood. Here, we show at single-cell resolution that HECs rely on gene regulatory networks driven by IRE1α-XBP1 and CREB3L1/2 transcription factors.

These networks upregulate enzymes and transporters that control inter-organelle metabolic fluxes for the step-wise assembly of sulfated O-glycan synthesis, while scaling the endoplasmic reticulum (ER) and Golgi apparatus, reinforcing cargo trafficking and organizing sequential glycosyltransferase deployment. Genetic and pharmacological perturbations show that these transcriptional circuits sustain lymph node HEC morphology and function in lymphocyte homing, and drive ectopic induction of HEV during inflammation.