Molecular mechanisms of protein function

Sloan-Kettering Inst Can Research, New York NY

Investigators

Abstract

Project Summary: The goals of this research program are to understand the molecular mechanisms underlying proteins and protein complexes that facilitate intracellular ion transport and ensure genomic integrity by replicating and repairing the genome. For proteins involved in membrane transport, we aim to elucidate the mechanisms by which ions are recognized and transported across the membrane as well as how the activities of these proteins are regulated. For those involved in maintaining genomic integrity, we will address how genomic features are recognized to recruit the replication and repair machineries to specific genomic loci. We employ a highly collaborative approach, combining high-resolution structure determination, electrophysiology, in vitro reconstitution, cell biology, computational analysis and mouse models to establish a holistic understanding of these proteins and protein complexes at the molecular level and their how dysregulation can lead to disease. We are currently focused on investigating four families of ion transport proteins including the lysosomal potassium and proton channel TMEM175, the CLC family of chloride channels and transporters, the inositol trisphosphate receptors and CLN7. TMEM175 is a lysosomal channel responsible for maintaining lysosomal pH that is critical for lysosomal function and homeostasis. We are identifying novel inhibitors of TMEM175 to better understand its physiological roles and determining how diverse stimuli coordinate to regulate its activity. Humans express 5 CLC transporters in the endolysosomal system, where they regulate ion and pH homeostasis. We are elucidating how lipids, accessory subunits and other stumuli regulate the activity of CLCs. Inositol trisphosphate receptors are tetrameric channels that release Ca2+ stored in the endoplasmic reticulum to stimulate diverse cellular pathways including fertilization, cell death and cell division. We aim to understand how IP3Rs are regulated by their diverse stimuli and how these regulatory stimuli result in Ca2+ oscillations. CLN7 is a lysosomal chloride channel that more closely resembles transporters than channels. We are investigating how CLN7 can selectively permeate chloride ions in the lysosome. Genomic integrity requires that the genome be duplicated during each cell cycle without errors. We are investigating how DNA structures, such as a G4-quadreplexes act as impediments to the DNA replication machinery and how these impediments can be overcome to complete replication. Collectively, these studies will reveal insights into protein function that will improve understanding of their roles in critical physiological processes. As dysregulation of any of these components can lead to disease, these studies will also provide insights into the molecular basis of disease.