Robert M. Larkin

Research Interests

We study signaling networks and processes that contribute to organelle biogenesis and function in plants, especially chloroplast biogenesis and function. Our current work focuses on three areas:

(1) We are studying light and plastid signals — two main regulators of chloroplast biogenesis. We found that plastid signals are endogenous regulators of light signaling and can affect light regulation of gene expression, chloroplast biogenesis, and development.

(2) Chlorophyll biosynthesis contributes to chloroplast biogenesis. We are studying a novel regulator of chlorophyll biosynthesis named GUN4. GUN4 stimulates Mg-chelatase, the enzyme that commits porphyrins to chlorophyll biosynthesis.

(3) We are studying membrane-tethered transcription factors that promote organelle function by contributing to intracellular signaling. We found a transcription factor that is tethered to membranes of the endoplasmic reticulum and defines a previously unknown branch of the heat-stress response. This work provides the first demonstration that the endoplasmic reticulum can contribute to heat tolerance.

Recent Publications

Adhikari, ND, Orler, R, Chory, J, Froehlich, JE, and Larkin, RM (2009) Porphyrins promote the association of GENOMES UNCOUPLED 4 and a Mg-chelatase subunit with chloroplast membranes. J Biol Chem 284: 24783-24796 Link to article

Ruckle, ME and Larkin, RM (2009) Plastid signals that regulate photomorphogenesis in Arabidopsis thaliana are dependent on GENOMES UNCOUPLED 1 and cryptochrome 1. New Phytol 182: 367-379 Link to article

Larkin, RM and Ruckle, ME (2008) Integration of light and plastid signals. Curr Opin Plant Biol. 11, 593-599. Link to article

Gao, H, Brandizzi, F, Benning, C, and Larkin, RM (2008) A membrane-tethered transcription factor defines a branch of the heat stress response in Arabidopsis thaliana.  Proc Natl Acad Sci USA 105:16398-403. Link to pdf

Ruckle ME, Demarco SM, Larkin RM (2007) Plastid signals remodel light signaling networks and are essential for efficient chloroplast biogenesis in Arabidopsis. Plant Cell 19: 3944-3960. Link to pdf

Verdecia MA, Larkin RM, Ferrer JL, Riek R, Chory J, Noel JP (2005) Structure of the Mg-Chelatase Cofactor GUN4 Reveals a Novel Hand-Shaped Fold for Porphyrin Binding. PLoS Biol. 3(5):e151 DOI: 10.1371/journal.pbio.0030151. Link to pdf

Larkin, R.M., Alonso, J.M., Ecker, J.R. and Chory, J. (2003) GUN4, a regulator of chlorophyll synthesis and intracellular signaling. Science 299, 902-906. Link to pdf

Mochizuki N., Brusslan J.A., Larkin R., Nagatani, A. and Chory, J. (2001) Arabidopsis genomes uncoupled 5 (GUN5) mutant reveals the involvement of Mg-chelatase H subunit in plastid-to-nucleus signal transduction. Proc. Natl. Acad. Sci. USA 98, 2053-2058. Link to pdf