Overview

Although the adverse health effects of heavy metals (e.g. cadmium [Cd2+] and lead [Pb2+]) have been known for a long time, exposure to heavy metals continues and even increases in some areas due to the boost in their production and emission into the environment. As a result, hundreds of Superfund Sites in the United States, among which are areas in New York State, are on the National Priority List (NPL). Chronic exposure of humans to heavy metals, either occupational or from food and air, leads to their accumulation in tissues and causes various diseases, including neurological degenerative conditions, dysfunction of vital organs, and cancer. Understanding the cellular metal detoxification mechanisms is critical for the cure and prevention of heavy metal-caused diseases and for developing methods of environmental remediation. We use interdisciplinary approaches and different model organisms (the nematode worm Caenorhabditis elegans, a model plant Arabidopsis thaliana and fission yeast Schizosaccharomyces pombe) to study one of the key pathways for heavy metal detoxification, the phytochelatin-dependent pathway, and transport processes that are required for maintenance of the concentration of heavy metals and by-products of metal toxicity in the cytosol below toxic limits. These studies will be used for developing new model systems for analyses of heavy metal detoxification processes in humans and generating novel tools for phytoremediation applications.

Research Focus

The research activities of my laboratory center on analyses of the molecular mechanisms that allow plants and some invertebrate animals, such as the nematode worm Caenorhabditis elegans, to tolerate heavy metals. Our research interests focus on two areas: 1) Identification of components of the phytochelatin-dependent pathway for heavy metal detoxification; 2) Analyses of transport processes that are required for maintenance of the concentration of heavy metals and by-products of metal toxicity in cytosol below toxic limits. Phytochelatins (PCs), a family of small thiol-rich peptides with the general structure (gamma-Glu-Cys)n-Xaa play a central role in heavy metal detoxification in plants, some fungi such as S. pombe and, as we recently demonstrated, in some invertebrates, as exemplified by C. elegans. Our discovery of the PC-dependent pathway in C. elegans provides us with a unique opportunity to analyze the components of the pathway using this model organism in parallel with plants. Aiming to define processes downstream of PC synthesis, we identified a half molecule ATP-binding cassette (ABC) transporter from C. elegans, CeHMT-1, that is acutely required for heavy metal tolerance and is homologous to a putative Cd?PC transporter from S. pombe, SpHMT-1. There are three ongoing projects in my laboratory: 1) Analyses of the molecular mechanisms of HMT-1-dependent heavy metal detoxification; 2) Analyses of biochemical and genetic interactions of ABC transporters required for heavy metal detoxification in C. elegans; 3) Development of a high throughput RNAi-based approach for identification of target genes involved in metal detoxification in plants with the goal of generating novel tools for remediation of heavy metal-contaminated soil and water using transgenic plants.

Outreach and Extension Focus

Although I do not have an extension appointment, the natural outreach of my research program would be education of the general public, farmers, and home gardeners in New York State (NYS) about heavy metals and their toxicity with the goal to improve public understanding that the safe management of heavy metals is critical to maintain profitable and productive agricultural systems, and is necessary to protect public health and the environment. This outreach component will be facilitated by collaboration with Ellen Harrison, Murray McBride and their colleagues at Cornell Waste Management Institute (CWMI, http://cwmi.css.cornell.edu/).

Instruction Focus

During my scientific career, I enjoyed a range of classroom and laboratory teaching opportunities, and I continue to seek teaching tools to improve my skills as an educator. I am a primary instructor for CSS/BioPL 642 : Mineral Nutrition: From Plants to Humans and I co-teach CSS 610: Physiology of Responses of Plants to Environmental Stresses." In these courses I attempt to convey molecular understanding of mechanisms that allow plants to tolerate adverse environmental conditions and by which plants absorb and translocate mineral nutrients from soil, and utilize them for growth and development.

Additional Links

• Vatamaniuk Lab
• Link to CALS Research portal
• Link to CALS Impact statements

Selected Publications

• Zhai, Z., Sooksa-nguan, T. and Vatamaniuk, O.K. Establishing RNAi as a reverse genetic approach for gene functional analysis in protoplasts. Plant Physiology, in Press http://www.plantphysiol.org/cgi/content/short/pp.108.130260?keytype=ref&ijkey=Jdal9nT4gkjF97d
• Sooksa-nguan, T., Yakubov, B., Kozlovskyy, V.I., Barkume, C.M., Howe, K.J., ThannhauserT.W., Rutzke, M.A., Hart, J.J., Kochian, L.V., Rea, P.A. and Vatamaniuk, O.K. Drosophila ABC transporter, DmHMT-1, confers tolerance to cadmium. DmHMT-1 and its yeast homolog, SpHMT-1,are not essential for vacuolar phytochelatin sequestration. J. Biol. Chem., in Press http://www.jbc.org/cgi/reprint/M806501200v1
• Romanyuk, N.D., Rigdenm, D.J., Vatamaniuk, O.K., Lang, A., Cahoon, R.E., Jez, J.M., Rea, P.A. (2006) Mutagenic definition of a papain-like catalytic triad, sufficiency of the N-terminal domain for single-site core catalytic enzyme acylation, and C-terminal domain for augmentative metal activation of a eukaryotic phytochelatin synthase. Plant Physiol., 141, 858-69
• Vatamaniuk O.K., Bucher E.A., Sundaram M.V. and Rea P.A. (2005) CeHMT-1, a putative phytochelatin transporter, is required for cadmium tolerance in Caenorhabditis elegans. J Biol Chem, 280, 23684-23690.
• Vatamaniuk, O.K., Mari, S., Lang A., Demkiv, L.O. and Rea, P.A. (2004) Phytochelatin synthase, a dipeptidyl transferase that undergoes multisite acylation with ?-glutamylcysteine during catalysis. STOICHIOMETRIC AND SITE-DIRECTED MUTAGENIC ANALYSIS OF AtPCS1-CATALYZED PHYTOCHELATIN SYNTHESIS. J. Biol. Chem. 279, 22449-22460.
• Rea P.A., Vatamaniuk O.K., Rigden D.J. (2004) Weeds, worms and more: papain's long-lost cousin, phytochelatin synthase. Plant Phys. 136, 2463-2474.
• Vatamaniuk O.K., Bucher E.A. and Rea P.A. (2002) Worms take the ?phyto' out of ?phytochelatins'. Trends in Biotechnol., 20, 61-64.
• Vatamaniuk O.K., Bucher E.A., Ward J.T. and Rea P.A. (2001) A new pathway for heavy metal detoxification in animals: phytochelatin synthase is required for cadmium tolerance in Caenorhabditis elegans. J. Biol. Chem., 276, 20817-20820.
• US Patent: Rea, P.A., Vatamaniuk, O.K., Mari, S., Lu, Y.-P., Schoeder, J.I., Kim, E.J., Clemens, S. US Patent No. 6,489,537: Phytochelatin synthases and uses therefor. Provisional patent filed August 1998; final US application filed May 1999. Allowance granted by USPTO June 2002. Patent issued December 3, 2002; Docket No. M-2262: Production of biomaterials for chelation applications. Provisional patent filed February 2000.
• Vatamaniuk, O.K., Mari, S., Lu, Y. -P. and Rea, P.A. (2000) Mechanism of heavy metal ion activation of phytochelatin (PC) synthase: blocked thiols are sufficient for PC synthase-catalyzed transpeptidation of glutathione and related thiol peptides. J. Biol. Chem., 275, 31451-31459.
• Vatamaniuk, O.K., Mari, S., Lu, Y.-P., and Rea, P.A. (1999) AtPCS1, a phytochelatin synthase from Arabidopsis: isolation and in vitro reconstitution. Proc. Natl. Acad. Sci. USA, 96, 7110-7115.

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