Ca2+ is a key element in cell signaling mechanism. As an ion, it contributes to the cell membrane potential. As a messenger, it interacts with tens of intracellular effector proteins, including many enzymes, and regulates diversified cellular functions: contraction, secretion, motility, gene expression, proliferation, differentiation, and apoptosis etc.

Resting intracellular free calcium level ([Ca2+]i) is usually low (100 nM), considered as a “zero / silent state”. Upon stimulations, [Ca2+]i can be raised up either by Ca2+ influx across the plasma-membrane or by Ca2+ release from intracellular store (the ER and related organelles) through variety of calcium channels. For example, store-operated Ca2+ channels (SOC) exist in numerous cell types, serving as the main source for Ca2+ entry in most non-excitable cells. Regulated activity of SOC channels is essential to the immune response and may play an important role in the cardiovascular system.

I am interested in the Ca2+ signaling transduction network. My goal is to discover and understand the missing pieces of this big puzzle, using techniques of molecular biology, biochemistry, and genetics. Currently I am focusing on the structures and functions of two newly identified protein components of SOC channels: Stim1 (the ER Ca2+ sensor for SOC activation) and Orai1 (the pore-forming subunit of SOC channels), which are both potential drug targets to treat autoimmune disorders and prevent organ transplant rejection.