Membrane contacts between the endoplasmic reticulum (ER) and mitochondria, known as mitochondria-associated membranes (MAM) are communication hubs that play crucial roles in diverse cellular functions, including ER to mitochondrial calcium (Ca2+) signaling, mitochondrial bioenergetics, lipid exchange, innate immunity, and apoptosis. The MAM is now emerging as a site for ER to mitochondrial trafficking of cellular proteins and viral proteins. This project characterizes a cytomegalovirus (CMV) protein, known as UL37 exon 1 protein (pUL37x1) that targets the MAM, alters some of its functions, and traffics from the ER to mitochondria. This project will examine how proteins use the MAM to traffic from the ER to mitochondria. It is projected that CMV pUL37x1 trafficking uses MAM vesicular or tether mediated mechanisms to traffic to mitochondria. This project will test whether MAM tethers or vesicular components underlie ER to mitochondrial trafficking using complementary approaches of inhibition (siRNAs, knock out cells, dominant negative mutants, and chemical inhibitors) and overexpression of MAM tether or MAM vesicular pathway components.
BROADER IMPACTS These studies will impact the intracellular protein trafficking field, as well as education and society (technology development). The project aims to understand MAM organization and its regulation, which affects cellular physiology and responses. The use of multifocal structured illumination microscopy (MSIM) will advance the intracellular protein trafficking field and, more broadly, cellular imaging. The studies will include training of undergraduate researchers, and in particular will continue to support the efforts of the participating labs in training underrepresented minorities in science. Because of the multidisciplinary approaches employed in this project, students will benefit from training in confocal live cell imaging, MSIM imaging, and molecular virology and biochemical approaches, participating in scientific discussions, and presenting their work at scientific meetings.
