Transport and Cellular Compartmentalization

Compartmentalization of metabolic pathways and other cellular functions is a hallmark of eukaryotic cells. This feature is extreme in plants due to the presence of organelles not found in most other eukaryotes – plastids. Plastids are a diverse group of interrelated organelles that perform a wide range of metabolic functions including photosynthesis, nitrogen and sulfur assimilation, and the synthesis of amino acids, starch and fatty acids. These functions are coordinated with metabolic processes in the cytosol and other organelles through dynamic exchange of metabolites and ions across the plastid inner envelope membrane.

My lab is studying transport processes that link the metabolic pathways in the plastid and cytosol. Transporters involved in the movement of phosphate (Pi) across the plastid inner membrane influence photosynthesis and the partitioning and storage of fixed carbon. We are using genetics, cell biology, biochemistry and molecular physiology to investigate the function and physiological roles of these transporters to coordinate metabolism with environmental conditions. We also use confocal microscopy and quantitative imaging of genetically encoded FRET-based biosensors to monitor Pi concentrations in different subcellular compartments in real time.

1. Raju, AS, Kramer, DM, Versaw, WK. Genetically manipulated chloroplast stromal phosphate levels alter photosynthetic efficiency. Plant Physiol. 2024;196 (1):385-396. doi: 10.1093/plphys/kiae241. PubMed PMID:38701198 PubMed Central PMC11376401.
2. Zhang, S, Daniels, DA, Ivanov, S, Jurgensen, L, Müller, LM, Versaw, WK et al.. A genetically encoded biosensor reveals spatiotemporal variation in cellular phosphate content in Brachypodium distachyon mycorrhizal roots. New Phytol. 2022;234 (5):1817-1831. doi: 10.1111/nph.18081. PubMed PMID:35274313 PubMed Central PMC9790424.
3. Sahu, A, Banerjee, S, Raju, AS, Chiou, TJ, Garcia, LR, Versaw, WK et al.. Spatial Profiles of Phosphate in Roots Indicate Developmental Control of Uptake, Recycling, and Sequestration. Plant Physiol. 2020;184 (4):2064-2077. doi: 10.1104/pp.20.01008. PubMed PMID:32999006 PubMed Central PMC7723077.
4. Voon, CP, Guan, X, Sun, Y, Sahu, A, Chan, MN, Gardeström, P et al.. ATP compartmentation in plastids and cytosol of Arabidopsis thaliana revealed by fluorescent protein sensing. Proc Natl Acad Sci U S A. 2018;115 (45):E10778-E10787. doi: 10.1073/pnas.1711497115. PubMed PMID:30352850 PubMed Central PMC6233094.
5. Zhang, W, Lo, IMC, Hu, L, Voon, CP, Lim, BL, Versaw, WK et al.. Environmental Risks of Nano Zerovalent Iron for Arsenate Remediation: Impacts on Cytosolic Levels of Inorganic Phosphate and MgATP^2- in Arabidopsis thaliana. Environ Sci Technol. 2018;52 (7):4385-4392. doi: 10.1021/acs.est.7b06697. PubMed PMID:29554421 .
6. Chiou, TJ, Versaw, WK, Fujiwara, T. Editorial overview: Cell signaling and gene regulation: nutrient sensing, signaling, and transport. Curr Opin Plant Biol. 2017;39 :iii-v. doi: 10.1016/j.pbi.2017.08.007. PubMed PMID:28866272 .
7. Versaw, WK, Garcia, LR. Intracellular transport and compartmentation of phosphate in plants. Curr Opin Plant Biol. 2017;39 :25-30. doi: 10.1016/j.pbi.2017.04.015. PubMed PMID:28570954 .
8. Banerjee, S, Garcia, LR, Versaw, WK. Quantitative Imaging of FRET-Based Biosensors for Cell- and Organelle-Specific Analyses in Plants. Microsc Microanal. 2016;22 (2):300-10. doi: 10.1017/S143192761600012X. PubMed PMID:26879593 .
9. Banerjee, S, Versaw, WK, Garcia, LR. Imaging Cellular Inorganic Phosphate in Caenorhabditis elegans Using a Genetically Encoded FRET-Based Biosensor. PLoS One. 2015;10 (10):e0141128. doi: 10.1371/journal.pone.0141128. PubMed PMID:26484766 PubMed Central PMC4615621.
10. Karlsson, PM, Herdean, A, Adolfsson, L, Beebo, A, Nziengui, H, Irigoyen, S et al.. The Arabidopsis thylakoid transporter PHT4;1 influences phosphate availability for ATP synthesis and plant growth. Plant J. 2015;84 (1):99-110. doi: 10.1111/tpj.12962. PubMed PMID:26255788 .