Molecular determinants of voltage-gated ION channels' localization and function

The National Institute of General Medical Sciences awarded The Trustees of the University of Pennsylvania $446,875 on March 6, 2026, under the Biomedical Research and Research Training program (CFDA 93.859) to characterize the molecular determinants of voltage-gated ion channel localization and function.

The project investigates how the Golgi-associated phosphoprotein 3 (GOLPH3) coordinates transport, stability, and activity of voltage-gated sodium and potassium channels at the cell plasma membrane. The research employs pharmacology, molecular biology, super-resolution microscopy, live fluorescence imaging, and electrophysiology to mechanistically link subcellular organelle organization and composition to ion channel function. Specific aims include defining ankyrin-G trafficking steps modulated by GOLPH3 and identifying the GOLPH3/ankyrin-G interactome, and elucidating how glycolipid synthesis influences sodium and potassium channel function. The work uses immortalized cell lines and primary hippocampal neurons to uncover conserved mechanisms.

Performance occurs in Philadelphia, Pennsylvania. The award carries a period of performance through February 28, 2031.

Abstract

Voltage-gated ION channels are expressed in multiple tissues and are among the most important drug targets for treatment of illnesses including chronic pain, muscular, neurological and cardiovascular disorders. Proper transport and organization of these channels at the plasma membrane is essential for their function. Despite decades of research, there still are fundamental gaps in our understanding of the mechanisms that transport and stabilize these channels at the cell surface. We recently discovered a new candidate protein that may coordinate the transport, stability and activity of voltage-gated sodium (NAV) and potassium (KV) channels at the plasma membrane - the golgi-associated phosphoprotein 3 (GOLPH3). The research programs delineated here aim to mechanistically characterize the downstream pathways and effectors that mediate GOLPH3's modulation of NAV and KV channels, including the recruitment of the scaffold protein ankyrin-g (ankg) and the synthesis of glycolipids. We will use a multiscale approach, combining pharmacology, molecular biology, super-resolution microscopy, live fluorescence imaging and electrophysiology, to causally link the subcellular organization and composition of the cell's organelles to ION channel function and cell physiology. We will also use different cellular models, including immortalized cell lines and primary hippocampal neurons, which will allow US to uncover fundamental, conserved mechanisms. We plan to: 1. Define the steps in ankg, NAV and KV channel trafficking that are modulated by GOLPH3 and identify the GOLPH3/ankg interactome, dissecting golgi dependent and independent mechanisms; 2. Elucidate how glycolipid synthesis influences the function of NAV and KV channels, dissecting transport mechanisms from modulation of channel conduction. Successful completion of this work will expand our current understanding of fundamental principles that govern ION channel localization and activity across cells. This knowledge may be applied in the future to the development of new strategies to improve ION channel function in multiple diseases, including neurodegeneration and cancer.