Rodney K Tweten, PhD

Dr. Tweten


OU Presidential Professor
George Lynn Cross Research Professor

Ph.D.: 1982, Kansas State University

Pre-OUHSC:
University of California at Los Angeles

Research Interests: Structural biology and biochemistry of bacterial protein toxins.

Teaching: Basic Bacteriology

Email: Rod-Tweten@ouhsc.edu

 


  

Research Emphasis

 Our research centers on the study of the mechanism of pore-forming toxins and proteins from prokaryotic and eukaryotic sources. Our studies are focused on the pore-forming mechanisms of the cholesterol dependent cytolysins (CDCs) from various pathogenic bacteria and more recently the membrane attack complex/perforin (MACPF) family of proteins that are involved in immune defense, development and pathogenesis of eukaryotic pathogens. An intriguing characteristic of these proteins is the ability of these soluble proteins to make the transition to a homo-oligomeric pore-forming complex on the membrane of eukaryotic cells. The mechanism by which they accomplish this transition is complex and each protein family contributes unique aspects to this process.   

                                                                 

                Ribbon representative of the Perfringolysin O crystal structure

The CDCs are produced by and contribute to the pathogenic mechanisms of a wide variety of Gram-positive bacterial pathogens and so the study of the CDCs (formerly the thiol-activated or oxygen labile toxins) is of considerable interest the fundamental bacterial pathogenesis and the protein chemistry of membrane-associated proteins. They are multifunctional proteins and exhibit the ability to affect cellular processes by pore-dependent and independent mechanisms. Our studies have provided the structural basis for the pore-forming mechanisms of the CDCs and revealed many novel aspects of this process. These studies have resulted form a long-term collaboration with Drs. Art Johnson (Texas A&M) and Michael Parker (St. Vincent's Institute of Medical Research, Australia).

 

The MACPF proteins were recently suggested to be ancient relatives of the CDCs due to the presence of a conserved structural fold that our collaborators and we have shown to be the membrane-spanning domain of the CDCs. The MACPF proteins comprise a large group of proteins that are associated with immune defense, development and pathogenesis of eukaryotic pathogens. Examples of MACPF immune defense proteins include perforin and the membrane attack complex of complement. Development related MACPF proteins include the Drosophila Torsolike protein that is involved in head and thorax patterning, and human astrotactin 1 and 2, which are involved in neuronal patterning. Several MACPF proteins have been identified in eukaryotic pathogens such as Toxoplasma and malaria, which have been shown to facilitate specific aspects of their pathogenic mechanisms. We are currently studying several of these proteins to understand their mechanism of pore formation. We are currently working with Drs. Michelle Dunstone and James Whisstock (Monash University, Australia) to understand the pore-forming mechanism of the MACPF proteins.    


Current Laboratory Personnel:

Joshua Burns, Postdoctoral Research Fellow

Jordan Evans, Graduate Student

Allison Farrand, Ph.D., Staff Scientist

Patricia Parrish, Research Assistant II

Selected Publications:

Czajkowsky, D. M., E. M. Hotze, Z. Shao, and R. K. Tweten. 2004. Vertical collapse of a cytolysin prepore moves its transmembrane β-hairpins to the membrane. EMBO J 23:3206-3215.

Giddings, K. S., J. Zhao, P. J. Sims, and R. K. Tweten. 2004. Human CD59 is a receptor for the cholesterol-dependent cytolysin intermedilysin. Nat Struct Mol Biol 11:1173-1178.

Ramachandran, R., R. K. Tweten, and A. E. Johnson. 2004. Membrane-dependent conformational changes initiate cholesterol-dependent cytolysin oligomerization and intersubunit β-strand alignment. Nat Struct Mol Biol 11:697-705.

Polekhina, G., K. S. Giddings, R. K. Tweten, and M. W. Parker. 2005. Insights into the action of the superfamily of cholesterol-dependent cytolysins from studies of intermedilysin. Proc Natl Acad Sci 102:600-605.

Ramachandran, R., R. K. Tweten, and A. E. Johnson. 2005. The domains of a cholesterol-dependent cytolysin undergo a major FRET-detected rearrangement during pore formation. Proc Natl Acad Sci 102:7139-7144.

Schuerch, D. W., E. M. Wilson-Kubalek, and R. K. Tweten. 2005. Molecular basis of Listeriolysin O pH-dependence. Proc Natl Acad Sci 102:12537–12542 

Soltani, C. E., E. M. Hotze, A. E. Johnson, and R. K. Tweten. 2007. Structural elements of the cholesterol-dependent cytolysins that are responsible for their cholesterol-sensitive membrane interactions. Proc Natl Acad Sci U S A 104:20226-20231.

LaChapelle, S., R. K. Tweten, and E. M. Hotze. 2009. Intermedilysin-receptor interactions during assembly of the pore complex: assembly intermediates increase host cell susceptibility to complement-mediated lysis. J Biol Chem 284:12719-12726.

Farrand, A. J., S. LaChapelle, E. M. Hotze, A. E. Johnson, and R. K. Tweten. 2010. Only two amino acids are essential for cytolytic toxin recognition of cholesterol at the membrane surface. Proc Natl Acad Sci U S A 107:4341-4346.

 Wickham, S. E., E. M. Hotze, A. J. Farrand, G. Polekhina, T. L. Nero, S. Tomlinson, M. W. Parker, and R. K. Tweten. 2011. Mapping the intermedilysin-human CD59 receptor interface reveals a deep correspondence with the binding site on CD59 for complement binding proteins C8alpha and C9. J Biol Chem 286:20952-20962.

Dowd, K. J., A. J. Farrand, and R. K. Tweten. 2012. The cholesterol-dependent cytolysin signature motif: a critical element in the allosteric pathway that couples membrane binding to pore assembly. PLoS Pathog 8:e1002787.

Dunstone, M. A., and R. K. Tweten. 2012. Packing a punch: the mechanism of pore formation by cholesterol dependent cytolysins and membrane attack complex/perforin-like proteins. Curr Opin Struct Biol 22:342-349.

Hotze, E. M., E. Wilson-Kubalek, A. J. Farrand, L. Bentsen, M. W. Parker, A. E. Johnson, and R. K. Tweten. 2012. Monomer-monomer interactions propagate structural transitions necessary for pore formation by the cholesterol-dependent cytolysins. J Biol Chem 287:24534-24543.

Wade KR, Hotze EM, Briles DE, Tweten RK. 2014. Mouse, but not human, ApoB-100 lipoprotein cholesterol is a potent innate inhibitor of Streptococcus pneumoniae pneumolysin. PLoS Pathog 10:e1004353.

Farrand AJ, Hotze EM, Sato TK, Wade KR, Wimley WC, Johnson AE, Tweten RK. 2015. The cholesterol-dependent cytolysin membrane-binding interface discriminates lipid environments of cholesterol to support beta-barrel pore Insertion. J Biol Chem 290:17733-17744.

Lukoyanova N, Kondos SC, Farabella I, Law RH, Reboul CF, Caradoc-Davies TT, Spicer BA, Kleifeld O, Traore DA, Ekkel SM, Voskoboinik I, Trapani JA, Hatfaludi T, Oliver K, Hotze EM, Tweten RK, Whisstock JC, Topf M, Saibil HR, Dunstone MA. 2015. Conformational changes during pore formation by the perforin-related protein pleurotolysin. PLoS Biol 13:e1002049.

Wade KR, Hotze EM, Kuiper MJ, Morton CJ, Parker MW, Tweten RK. 2015. An intermolecular electrostatic interaction controls the prepore-to-pore transition in a cholesterol-dependent cytolysin. Proc Natl Acad Sci U S A 112:2204-2209.