Mitochondria form elaborate reticular networks that make physiologically important contacts with nearly every
other organelle. Recently, mitochondrial membrane contact sites (MMCSs) have been shown to play a role in
regulating mitochondrial function. Beyond physically tethering organelles, MMCSs have been implicated in
interorganelle communication, modulating mitochondrial fusion and fission, and adapting the mitochondrial
network to function under stress conditions. Despite progress in defining the molecular composition of individual
MMCSs, little is known about the functions of MMCSs or how they are regulated in space and time. Previous
studies have focused on individual MMCSs under a narrow range of biological conditions; however, multiple
MMCSs exist simultaneously, creating a dynamic network that controls the function of mitochondria. Thus,
defining the functions of MMCSs and dissecting how these functions are coregulated in space and time to
modulate mitochondrial function represents a well-recognized gap in knowledge. To address this complex
problem, this proposal will analyze the simplified MMCS network of the budding yeast Saccharomyces
cerevisiae. A multidisciplinary approach will be used to characterize novel functions of the mitochondria-ER-
cortex anchor (MECA) and probe how these functions are coregulated with other MMCSs to adapt the
mitochondrial network to function under various stresses. MECA forms a unique tripartite organelle contact site
between mitochondria, the ER, and the plasma membrane. Work in Aim 1 will determine the mechanism and
function of contact between MECA and the ER and test the hypothesis that MECA-ER contacts are involved in
mitochondrial respiratory function. Work in Aim 2 will use unbiased screening approaches to identify novel genes
and metabolites involved in mitochondrial functions that are regulated by MECA. Work in Aim 3 will characterize
the dynamic regulation of MECA and other MMCSs in response to environmental or mitochondrial stresses and
test the hypothesis that MMCSs are coregulated to adapt the mitochondrial network for optimal function. This
proposal will identify novel functions of MECA and describe how this contact site and others are regulated
through space and time. This work will extend beyond the characterization of a MMCS in a single context and
begin dissecting how MMCSs are regulated at a systems level to modulate mitochondrial function.
The training plan in this proposal is designed to teach the skills required to operate as an independent researcher.
The central focus will be training in interdisciplinary research and career development skills. This proposal
provides the opportunity to learn state-of-the-art biochemical, genetic, and systems level approaches to ask
fundamental questions about organelle biology. Scientific communication and networking skills will be
strengthened by authoring scientific papers and presenting at group meetings and conferences. This proposal
also provides training in mentorship, ethical research practices, and promoting diversity and inclusion in science.