The health of the ER is monitored by a triad of ER sensor transmembrane proteins ATF6, Ire1a, and Perk. Accumulation of misfolded proteins in the ER results in ER stress and activates the sensor proteins and initiates the Unfolded Protein Response (UPR) to restore homeostasis. If protein folding is unresolved, elevated UPR induces stimulates cytokine production and cell death. Another aspect of ER homeostasis is the ER associated degradation (ERAD) - a retrograde pathway that recognizes and clears misfolded proteins from the ER.
Role of UPR genes in skeletal health and pathology. We use mouse models to delete the UPR genes in osteoblast lineage cells and understand the mechanisms by which the UPR regulates their differentiation and bone mass. We also use murine models to dissect how UPR dysregulation contributes to pathologic bone loss.
Role of ERAD in bone health. We use murine models to discern the role of ERAD in acquisition of adult bone. Collaboration with Dr. Ling Qi (University of Michigan).