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Carole Dabney-Smith, Assistant Professor
Ph.D. 2001
University of Tennessee
Room 132 Hughes
513-529-8091
adabney@muohio.edu |
Protein sorting, protein transport, protein-protein
interactions, membrane protein structure/function, and organelle biogenesis
My research focus is protein sorting within
cells. We investigate mechanisms of protein transport as it relates to
organelle biogenesis. Our research utilizes biochemical and biophysical
approaches to cell biology in organello and in vitro, as well as whole cell
approaches in vivo.
We focus our studies on chloroplasts and mitochondria from plant cells. Most
proteins found in those organelles are encoded by genomic DNA and are
synthesized in the cytoplasm as higher molecular weight precursor proteins
which must cross membranes in order to get to their site of function.
Survival of the plant and proper development of the organelle depend upon
accurate sorting of proteins to their correct sub-organellar location.
We study a recently discovered system that transports fully folded proteins
into the thylakoid lumen using only the thylakoid proton motive force as
energy source. We also study the homologous system in mitochondria which
likely transports proteins from the matrix to the inner membrane space. This
system, the Tat system (Twin Arginine Transport), presents an intriguing and
challenging mechanistic problem because it transports folded domains of
varying diameters without rendering the membrane leaky to protons and ions.
Tat systems are now known to be widely present in bacteria and archaea as
well as in the prokaryote-derived organelles: chloroplasts and plant
mitochondria. However Tat systems are not found in animal cells. Thus they
are likely to operate by ancient and possibly simple mechanisms, an enticing
system for in vitro and reconstitution analysis. Tat systems may also be
important targets for antimicrobial agents because they are involved in
secretion of virulence factors for animal and plant diseases. For example,
several human pathogens, such as Pseudomonas aeruginosa, Yersinia
pseudotuberculosis, and Legionella pneumophila and at least one
agriculturally significant pathogen, P. syringae pv. Tomato DC3000, require
a functional Tat system to be virulent. Understanding the mechanism of
protein transport by this system may provide new approaches to combating
bacterial infections.
Publications
Auldridge ME, Block A, Vogel JT, Dabney-Smith C, Mila I, Bouzayen M,
Magallanes-Lundback M, DellaPenna D, McCarty DR, Klee HJ. 2006.
Characterization of three members of the Arabidopsis carotenoid cleavage
dioxygenase family demonstrates the divergent roles of this multifunctional
enzyme family. Plant J 45(6):982-993.
Dabney-Smith, C; Mori, H; and Cline K. 2006. Oligomers of Tha4 organize at
the thylakoid Tat translocase during protein transport. J Biol Chem
281:5476-5483.
Dabney-Smith, C; Mori, H; and Cline, K. 2003. Requirement of a Tha4
conserved transmembrane glutamate in thylakoid Tat translocase assembly
revealed by biochemical complementation. J Biol Chem 278:43027-43033.
Fincher, V; Dabney-Smith, C; and Cline, K. 2003. Functional Assembly of
Thylakoid pH-Dependent/Tat Protein Transport Pathway Components In Vitro. J
Biol Chem 270:4930-4941.
Schleiff, E; Sveshnikova, N, Tien, R, Soll, J, Wright, S, Dabney-Smith, C,
Subramanian, C, and Bruce, BD. 2002. Structural and nucleotide requirements
for transit peptide recognition by the chloroplast translocation machinery
and the cytosolic domain of the receptor, Toc34. Biochemistry 41:1934-1946.
Lee, SK; Dabney-Smith, C; Hacker, D; and Bruce, BD. 2001. Interaction of the
southern cowpea mosaic virus coat protein with membranes. Virology
291:299-310.
Dabney-Smith, C; van den Wijngaard, PW; Treece, Y; Vredenberg, W; and Bruce,
BD. 1999. The C-terminus of a chloroplast precursor modulates its
interaction with the translocation apparatus. J Biol Chem 274:32351-32359.
van den Wijngaard, PW; Dabney-Smith, C; Bruce, BD; and Vredenberg, WJ. 1999.
The mechanism of inactivation of a 50-Picosiemens envelope anion channel
during chloroplast protein import. Biophysical Journal 77:3156-3162.
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