Dr. John Dawson

Awards:

Research:
2004-2009 New Investigator Award, Heart and Stroke Foundation of Canada
2005 Reginald Nadeau Thematic Symposium Award, National Research Forum for Young Investigators in Circulatory and Respiratory Health
2009 ASBMB Education Conference meeting registration grant

Teaching:
2006 CBS Award for Excellence in Teaching, University of Guelph
2006 UGFA Special Merit Award based on Innovation in the Classroom, University of Guelph
2007 Provost’s Award for Innovation in Teaching, University of Guelph
2012 UGFA Distinguished Professorial Teaching Award, University of Guelph
2012 International Desire2Learn Edge Challenge, first runner-up

Research Interests:

My research focuses on the structure and function of the actin protein. My laboratory uses biochemical and biophysical approaches to develop actin complexes for structural work and to explore the relationships between natural variants in the cardiac actin gene and the development of heart diseases. I was the first to produce a crystal structure of a complex derived from F-actin. My lab was among the first to develop the baculovirus expression system for actin proteins, opening the doors to new horizons of actin research that were out of reach. Currently, my lab is at the forefront of the F-actin structure field and the human cardiac actin field.

Projects Recently Completed:

We recently completed the characterization of seven human cardiac actin variant proteins expressed in patients with either hypertrophic or dilated cardiomyopathy. We found subtle biochemical changes in these proteins, with some that were unstable, some with polymerization defects, and others that did not exhibit significant intrinsic property changes. These data support the idea that the development of cardiomyopathy is a complex process that involves many pathways to the disease.

We also headed up a collaborative project to discover the causative protein changes in Doberman Pinschers with dilated cardiomyopathy. We sequenced 10 genes from five affected Doberman Pinschers and five unaffected cross-breed dogs. We did not find any single segregating change in the Dobermans, but did find one mutation in the alpha-actinin gene that was found in two of the affected dogs; this result needs to be followed up.

Projects in Progress:

We are moving forward with the production and characterization of other human cardiac actin variants found in the human population, focusing on making connections between the molecular changes we observe and the pathophysiology of the disease. We are currently writing up our results examining the interactions between cardiac actin variant proteins and myosin, where we found evidence to support the hypothesis that enhanced actomyosin activity contributes to the development of hypertrophic cardiomyopathy. To examine the effects of cardiac actin mutation on a whole animal model, we are establishing a zebrafish model for the expression of cardiac actin variants. Our preliminary results are promising!

Facilities/Unique Equipment:

FPLC protein purification system, spectrophotometer, fluorimeter, PCR, tabletop ultracentrifuge
Yeast culturing facility, baculovirus production and protein expression facility, recombinant protein expression and purification from E. coli Actin purification and characterization

Administrative and Professional Activites/Interests:

Chair, Biochemistry Undergraduate Curriculum Committee, 2007-2010
Chair, Molecular and Cellular Biology Departmental Undergraduate Curriculum Committee 2010-present
Scholarship of Teaching and Learning Fund peer review committee: April 4, 2011

Funding:

Present:
Heart & Stroke Foundation GIA Dawson (PI) 07/01/2012 — 06/30/2014
Sarcomere Protein Interactions in Cardiomyopathies The major goals of this project are (1) determine the intrinsic properties of all know ACTC proteins, (2) determine the changes to interactions with myosin binding protein-C, (3) determine the changes to interactions with myosin and regulated filaments, (4) express ACTC variants in cardiomyocytes.

NSERC Discovery Grant Dawson (PI) 04/01/2009 — 03/31/2014
Biochemical and Structural Characterization of Non-polymerizing Actin Dimers and Trimers
The major goals of this program are (1) produce ADPr-actin dimers and trimers, (2) characterize their intrinsic properties, (3) characterize their interaction with ABPs, and (4) determine their crystal structure.

Past:
Heart & Stroke Foundation GIA Dawson (PI) 07/01/2008 — 06/30/2011
Expression and characterization of human cardiac actin mutants linked to hypertrophic and dilated cardiomyopathies

CIHR Operating Grant Dawson (PI) 2004-2007
Biochemical characterization of human cardiac actin mutants linked to hypertrophic and dilated cardiomyopathies

PetTrust Project Grant Dawson, Pyle, O’Sullivan 2005
Genetic mutations in Doberman DCM

NSERC Discovery Grant Dawson (PI) 2004-2009
Characterization of non-polymerizing actin mutants

NIH R01 Subcontract Robert Fletterick (PI) 2003-2007
Conformational changes in actin

Other Tidbits:

1998-present American Society of Cell Biology
2001-present Canadian Society for Biochemistry and Molecular and Cellular Biology
2009-present Society for Teaching and Learning in Higher Education

Links:

Personal Lab Page
Departmental Page

Students:

Anillo, Maria (M.Sc.)
Matovic, Tijana (M.Sc.)
Mishra, Vadika (M.Sc.)

Publications:

1. Arora, P.D., Wang, Y., Bresnick,. A, Dawson, J., Janmey, P.A., McCulloch, C.A. (2013) Collagen Remodeling by Phagocytosis is determined by Collagen Substrate Topology and by Calcium-Dependent Interactions of Gelsolin with Non-Muscle Myosin IIA in Cell Adhesions. Mol Biol Cell. 24(6):734-47.
2. Mundia, M.M., Demers, R.W., Chow, M.L., Perieteanu, A.A., and Dawson, J.F. (2012) Subdomain Location of Mutations in Cardiac Actin Correlate with Type of Functional Change. PLoS ONE, 7(5): e36821. doi:10.1371/journal.pone.0036821.
3. Mohammad I., Arora P.D., Naghibzadeh, Y., Wang, Y., Li, J., Mascarenhas, W., Janmey. P.A., Dawson, J.F., and McCulloch, C.A. (2012) Flightless I is a focal adhesion-associated actin capping protein that regulates cell migration. FASEB J, 26(8):3260-72.
4. O’Sullivan, M.L., O’Grady, M.R., Pyle, W.G., and Dawson, J.F. (2011) Evaluation of ten genes encoding cardiac proteins in Doberman pinschers with dilated cardiomyopathy. J. Am. Vet. Res, 72(7):932-9.
5. Perieteanu, A.A., Visschedyk, D.D., Merrill, A.R., and Dawson, J.F. (2010) ADP-ribosylation of Crosslinked Actin Generates Barbed-end Polymerization Deficient F-actin Oligomers. Biochemistry, 49: 8944-54.
6. Morrison, S.S, Loncar, A., and Dawson, J.F. (2010) Non-polymerizing Long-pitch Actin Dimers that Interact with Myosin. Arch. Biochem. Biophys., 501:188-94.
7. Visschedyk, D.D., Perieteanu, A.A., Turgeon, Z.J., Fieldhouse, R.J., Dawson, J.F., and Merrill, A.R. (2010) Photox: A novel actin-targeting mono-ADP-ribosyltransferase from Photorhabdus luminescens. J. Biol. Chem., 285(18):13525-34.
8. Saha, S., Mundia M.M., Zhang, F., Demers R.W., Korobova, F., Svitkina, T., Perieteanu, A.A., Dawson, J.F., and Kashina, A. (2010) Arginylation regulates intracellular actin polymer levels by modulating actin properties and differential binding of capping and severing proteins. Mol. Biol. Cell, 21(8):1350-61.
9. Yates, S.P., Loncar, A., and Dawson, J.F. (2009) Actin polymerization is controlled by residue size at position 204. Biochem. Cell Biol., 87(5): 853-865.
10. Pengelly, K., Loncar, A., Perieteanu, A.A., and Dawson, J.F. (2009) Cysteine Engineering of Actin Self-assembly Interfaces. Biochem. Cell Biol., 87(4): 663-675.
11. Ahmed, M.A., Bamm V.V., Shi, L., Steiner-Mosonyi, M., Dawson, J.F., Brown, L.S., Harauz. G., and Ladizhansky, V. (2008) Induced secondary structure and polymorphism in an intrinsically disordered structural linker of the central nervous system – Solid-state NMR and FTIR spectroscopy of 18.5 kDa myelin basic protein (MBP) bound to actin. Biophys J, 96:180-91.
12. Perieteanu, A.A., Sweeting, B., and Dawson, J.F. (2008) The Real-Time Monitoring of the Thermal Unfolding of Tetramethylrhodamine Labeled Actin. Biochemistry, 47: 9688-9696.
13. Isgandarova S., Jones L., Forsberg D., Loncar A., Dawson J., Tedrick K., and Eitzen G. (2007) Stimulation of actin polymerization by vacuoles via Cdc42p-dependent signaling. J. Biol. Chem., 282:30466-30475.
14. Yates, S.P., Otley, M.M., and Dawson, J.F. (2007) Overexpression of Cardiac Actin with Baculovirus is Promoter Dependent. Arch. Biochem. Biophys., 466: 58-65.
15. Teal, D.J., and Dawson, J.F. (2007) Yeast Actin with a Subdomain 4 Mutation (A204C) Exhibits Increased Pointed-End Critical Concentration. Biochem. Cell Biol., 85: 319-325.
16. Morrison, S.S., and Dawson, J.F. (2007) A High-Throughput Assay Shows DNase-I Binds Actin Monomers and Polymers with Similar Affinity. Analytical Biochem., 364:159-164.
17. Sweeting, B., and Dawson, J.F. (2006) Purification and Characterization of a Nonpolymerizing Long-Pitch Actin Dimer. Biochem. Cell Biol., 84: 695-702.
18. Rutkevich, L.A., Teal, D.J., and Dawson, J.F. (2006) Expression of actin mutants to study their roles in cardiomyopathy. Can. J. Physiol. Pharmacol. 84: 111-119.
19. Churchman, L.S., Okten, Z., Rock, R.S., Dawson, J.F., and Spudich, J.A. (2005) Single molecule high-resolution colocalization of Cy3 and Cy5 attached to macromolecules measures intramolecular distances through time. PNAS USA, 102: 1419-1423.
20. Summerscales, J., and Dawson, J.F. (2004) Probing Dictyostelium severin structure and function by cross-linking to actin. Biochem. Cell Biol., 82: 343-350. (Cover)
21. Dawson, J.F., Sablin, E.P., Spudich, J.A., and Fletterick, R.J. (2003) Structure of an F-actin trimer disrupted by gelsolin and implications for the mechanism of severing. J. Biol. Chem., 278: 1229-1238.
22. Sablin, E.P., Dawson, J.F., VanLoock, M.S., Spudich, J.A., Egelman, E.H., and Fletterick, R.J. (2002) How does ATP hydrolysis control actin’s associations? PNAS SA, 99: 10945-10947.