The Emr lab studies the regulation of cell signaling pathways by phosphoinositide kinases, vesicle-mediated transport reactions, and selective ubiquitin modifications. Research in the lab focuses on three main topics: (1) the genetics of endocytic trafficking and receptor down-regulation (mediated by the ART and ESCRT machinery); (2) genetic and biochemical analysis of phosphoinositide lipid- and ubiquitin-dependent membrane sorting and signaling pathways and (3) defining the pathways for maintaining the composition and quality of membrane proteins both at the plasma membrane and the lysosomal membrane (nutrient transporters, channels, receptors, etc.).
The endo-lysosome Protein Quality Control (PQC) pathway monitors membrane proteins at multiple, sequential endocytic organelles to prevent their accumulation of damaged or mistargeted proteins. The Emr lab is interested in discovering and understanding the roles for all the components in protein quality control in the endocytic pathway, how their functions and localization is regulated, and which cargos are targeted for degradation in response to specific cues. The Emr lab identified and characterized a family of arrestin-related trafficking adaptors,
or ARTs, which recruit the Rsp5 ubiquitin ligase to specific targets at theplasma membrane. They also discovered the ESCRT (Endosomal Sorting Complexes Required for Transport) complexes as essential components of the endocytic sorting pathway. The ESCRT complexes play critical roles in the down-regulation and degradation of plasma membrane receptors and transporters. ESCRTs also are essential for the budding of many retroviruses including HIV, the abscission event during cytokinesis, reformation of the nuclear membrane following mitosis, and the repair of plasma membrane damage.
