Mitochondrial-Nuclear Interactions

ATP production via mitochondrial oxidative phosphorylation (OXPHOS) is fundamental to cellular and organismal functions in eukaryotes. The electron transport chain (ETC) is the engine of this process, comprising mitochondrial-encoded and nuclear-encoded proteins. Recent work in our lab revealed tight co-evolution between mitochondrial genomes and interacting nuclear genes, yet we failed to support the widely invoked nuclear compensation mechanism that is predicted to maintain this crucial partnership. We are working to understand how amino acid changes in one partner affects chimeric protein function.

Mitochondrial Alternative Oxidase (AOX)

Alternative Oxidase (AOX) is a common, but understudied, ETC component that allows for metabolic flexibility, helping organisms endure respiratory stress. Our recent work has mapped the wide taxonomic distribution of AOX orthologs across the tree of life, suggesting its an ancestral trait in eukaryotes,. Current projects on this topic include determining the functional role of AOX in animals, many of which tend to share facultatively sexual and/or hypoxia-tolerant life-histories.

Pathogen Bioenergetics

Pathogens face variable –often harsh– environments across their life cycles that span wide ranges of pH, temperature, oxygen levels, nutrient availability, and host immune responses, which pose challenges to metabolic machinery. In aerobic environments, oxidative phosphorylation-based respiration brings high yields of biological energy in the form of ATP, but also introduces vulnerabilities to environmental stressors that inhibit canonical mitochondrial electron transport chain (ETC) pathways. Respiratory stress can be deadly, but many and diverse eukaryotes avoid or tolerate this stress because they have a branched ETC that allows for metabolic flexibility. That is, in addition to the cytochrome pathway (CIII and CIV) where electron flux from reducing equivalents terminates in complex IV to reduce molecular oxygen to water, there is a second exit for electrons via the alternative oxidase (AOX). AOX is present in many eukaryotic pathogens (fungi and protists) that infect vertebrates. Our lab is investigating if and how AOX mediates the disease ecology of pathogens that infect amphibians, snakes, turtles, bats, and humans.

Vertical Divider

 

Projects ready for students to develop further

The evolution of sex, mitochondrial mutation rates, mitonuclear interactions, AOX function in animals, genomics of crustacean carotenoid coloration

Facultative Sex

Environment-Physiology interactions on mode of reproduction

 mtDNA Mutation Rates

Mitochondrial dynamics and mutation accumulation rates

Carotenoid Coloration in Animals

 

If I am known at all, it is mostly for my Ph.D. work on carotenoid coloration physiology and evolution in animals. Our group will still pursue these topics in the future, but are not currently. Here are some links:

Carotenoid metabolism strengthens the link between feather coloration and individual quality

What maintains signal honesty in animal colour displays used in mate choice?

Red coloration in an anchialine shrimp: carotenoids, genetic variation, and candidate genes

Carotenoid ornaments and the spandrels of physiology: a critique of theory to explain condition dependency

---

Painted Bunting

Investigating the molecular and structural basis for the coloration of the most colorful bird in North America
Now Published: Painting the Bunting: Carotenoids and structural elements combine to produce the feather coloration of the male Painted Bunting

Sapsucker Hybridization

Hybridization, mitochondrial divergence, and ketocarotenoid production

Volcano Shrimp

Population-specific ketocarotenoid production in Halocaridina rubra

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.