Sharon Campbell

Research: Regulator molecules in cell growth control and cell adhesion

Sharon Campbell

Professor of Biochemistry and Biophysics
(PhD - Yale University)

120 Mason Farm Road, CB# 7260
3093 Genetic Medicine
Chapel Hill, NC 27599-7260

Campbell Lab Website


  • Battle Distinguished Cancer Research Award - 2014
  • Phillip & Ruth Hettleman Prize - 2001
  • Jefferson Pilot Award - 1998


GTPases:  Aberrant regulation RAS and RHO GTPases is linked to a variety of disease states, including cancer, cardiovascular and neurological disorders.  RAS, in particular, has been a topic of intense investigation, as oncogenic RAS mutations cause constitutive RAS activation and are prevalent in cancer.  We have a longstanding history studying RAS proteins.  In our earlier studies, we applied novel four dimensional nuclear magnetic resonance (NMR) approaches to determine the first solution structure of the RAS proto-oncogene.  Subsequently, my group at the University of North Carolina identified and solved the NMR solution structure of a novel RAS binding site in the RAF kinase, that is required for RAF activation of the mitogen activated protein kinase cascade.  Our work has also elucidated how post-translational modifications of RAS, in particular, cysteine oxidation and ubiquitin modification lead to RAS activation. Through these efforts, our lab developed novel chemical ligation and radical detection methods to characterize RAS post-translational modifications.  Importantly, redox and ubiquitin modification of RAS contributes to RAS-mediated tumorigenesis. Our lab also showed that other members of the RAS superfamily (e.g., RHO GTPases) are regulated by these post-translational modifications, indicating conservation of these important regulatory mechanisms within the RAS superfamily of GTPases. We have recently extended these studies to investigate additional lysine modifications (acetylation, methylation) in RAS proteins. A current research interest in our lab lies in characterizing how residue and site-specific mutation differences in Ras proteins lead to distinct signaling and tumorigenic signatures. In a recent paper with the Sharpless lab (UNC), we characterized two different oncogenic Ras mutations to elucidate why one activating mutation promotes Melanoma whereas the other does not.  Understanding these differences could lead to mutation specific anti-cancer therapies. We have most recently initiated NMR structural studies on the heterotrimeric Gai subunit, in collaboration with the Dohlman lab at UNC.  Heterotrimeric G proteins are molecular switches that stimulate intracellular signalling cascades in response to activation of G-protein-coupled receptors (GPCRs) by extracellular stimuli. Our efforts here are centered on identification and characterization of inhibitors and mutations that activate and deactivate the Ga subunit.

  1. Sequential Assignment of the Backbone Nuclei (1H, 15N, 13C) of H-Ras.GDPUsing a Novel 4D NMR Strategy, SL Campbell-Burk, PJ Domaille, MA Starovasnik, ED Laue, W Boucher, J Biomol NMR 1992 2, 639-646.
  2. Four Dimensional Triple Resonance NMR Methods for the Assignment of Backbone Nuclei in Proteins, ED Laue, W Boucher, PJ Domaille, SL Campbell-Burk, J Am Chem Soc 1992 114, 2262-2264.
  3. The Solution Structure and Dynamics of Ras p21.GDP Determined byHeteronuclear Three and Four Dimensional NMR Spectroscopy, PJ Kraulis, PJ Domaille, SL Campbell-Burk, TA van Aken, ED Laue, Biochemistry 1994 33, 3515-3531.
  4. Mott HR, Carpenter JW, Zhong S, Ghosh S, Bell RM, Campbell SL. The solutionstructure of the Raf-1 cysteine-rich domain: a novel RAS and phospholipid binding site. Proc Natl Acad Sci U S A. 1996 Aug 6;93(16):8312-7. PubMed PMID: 8710867; PubMed Central PMCID: PMC38667.
  5. A Novel Mechanism for Nitric Oxide Action and its Implications on the RAS Guanine Nucleotide Triphosphatase, JG Williams, J Heo, K Pappu, SL Campbell, Proc Natl Acad Sci USA 2003, 100(11); 6376-6381.  PMID: 12740440.
  6. Baker R, Lewis SM, Sasaki AT, Wilkerson EM, Locasale JW, Cantley LC,Kuhlman B, Dohlman HG, Campbell SL. Site-specific monoubiquitination activates RAS by impeding GTPase-activating protein function. Nat Struct Mol Biol. 2013 Jan;20(1):46-52. PubMed PMID: 23178454; PubMed Central PMCID: PMC3537887.
  7. Burd CE, Liu W, Huynh MV, Waqas MA, Gillahan JE, Clark KS, Fu K, MartinBL, Jeck WR, Souroullas GP, Darr DB, Zedek DC, Miley MJ, Baguley BC, Campbell SL, Sharpless NE. Mutation-Specific RAS Oncogenicity Explains N-RAS Codon 61 Selection in Melanoma. Cancer Discov. 2014 Sep 24. pii: CD-14-0729. PubMed PMID: 25252692.

Cell Adhesion Proteins:  Our laboratory studies tumor suppressor (Vinculin) and tumor promoter (FAK, paxillin, palladin) proteins that control cell morphology and motility.  Deregulation of cell motility plays an important role in cell metastasis, often the leading cause of cancer deaths.  Our research efforts have elucidated protein-protein and protein-membrane interactions critical for regulated cell movement. Our group’s most recent studies of the cell adhesion protein, Vinculin, have focused on the Vinculin tail domain (Vt) and binding interactions with inositol phospholipids and actin. We have identified Vt regions important for phospholipid binding and membrane insertion, actin binding and actin bundling. We identified and characterized Vt variants that specially disrupt actin binding, and in collaboration with Clare Waterman’s group (NHLBI, NIH), applied super-resolution cellular microscopy approaches to analyze the role of Vinculin in integrating F-actin and focal adhesion dynamics. We then showed that Vinculin functions as a molecular clutch to extract energy from the actin cytoskeleton and use it to move the whole cell across a substrate. We also found that coordinate binding of actin with talin promotes vinculin activation.  Actin binding to Vinculin also plays a key role in the sub-cellular distribution of Vinculin within focal adhesions. Although models for how Vinculin recognizes F-actin had been reported, our identification of a new actin binding interface on Vt, led us to examine alternative models for the Vt/actin complex.  We have recently obtained one of the highest resolution cryo-electron microscopy (EM) reconstructions of a protein/actin complex (Vt/actin complex) currently available, in collaboration with the Alushin lab at NIH.  Our structure is consistent with the new or alternative actin interface proposed by our lab, and provides new insights into actin induced conformational changes in Vinculin that promote Vinculin dimerization and actin filament bundling.  Our current efforts are geared at understanding the structure of the actin-induced dimer, how the Vinculin dimer regulates actin reorganization and how the splice variant, Metavinculin, coordinates with Vinculin to reorganize actin filaments.  We are also studying how Vinculin inserts in the membrane through specific interactions with the inositol phospholipid, PIP2, and how this interaction regulates Vinculin localization, activation and focal adhesion turnover.

  1. Shen K, Tolbert CE, Guilluy C, Swaminathan VS, Berginski ME, Burridge K,Superfine R, Campbell SL. The vinculin C-terminal hairpin mediates F-actin bundle formation, focal adhesion, and cell mechanical properties. J Biol Chem. 2011 Dec 30;286(52):45103-15. PubMed PMID: 22052910; PubMed Central PMCID: PMC3247952.
  2. Thievessen I, Thompson PM, Berlemont S, Plevock KM, Plotnikov SV, Zemljic-Harpf A, Ross RS, Davidson MW, Danuser G, Campbell SL, Waterman CM. Vinculin-actin interaction couples actin retrograde flow to focal adhesions, but is dispensable for focal adhesion growth.  J Cell Biol. 2013 Jul 8;202(1):163-77.
  3. Thompson PM, Tolbert CE, Shen K, Kota P, Palmer SM, Plevock KM, Orlova A, Galkin VE, Burridge K, Egelman EH, Dokholyan NV, Superfine R, Campbell SL. Identification of an actin binding surface on vinculin that mediates mechanical cell and focal adhesion properties. Structure. 2014 May 6;22(5):697-706. Epub 2014 Mar 27. PubMed PMID: 24685146; PubMed Central PMCID: PMC4039106.
  4. Case, LB, Baird, M, Shtengel, G, Campbell, SL, Hess, H, Davidson, MD and Waterman, C.  Nature Cell Biology.  Molecular mechanism of vinculin activation and nano-scale spatial organization in focal adhesions.  Nat Cell Biol.  2015. Jun 8.  Epub ahead of print.  PMID: 26053221. 
  5. Lim, LY, Thompson, PM, Lee, HT, Pershad, M, Campbell, SL and Alushin, GM.  The structural basis of actin organization by vinculin and metavinculin.  J. Mol. Biol. 2016. 428:10-25.

Research Tools

Our laboratory employs multidisciplinary approaches to investigate these problems. While our main structural tool is high field NMR spectroscopy, we also employ other biophysical and biochemical methods including various computer modeling and computational approaches, fluorescence spectroscopy, biochemical characterization of binding interactions and enzyme activity. Most of our studies are conducted in collaboration with laboratories that focus on molecular and cellular biological aspects of these problems. This allows us to direct cell-based adhesion, motility, signaling and transformation analyses.

RECENT PUBLICATIONS  pubmed.png(click for full publication list)

  • The Structural Basis of Actin Organization by Vinculin and Metavinculin. Kim LY, Thompson PM, Lee HT, Pershad M, Campbell SL and Alushin GM. J Mol Biol. 2016; 428(1):10-25. [Epub ahead of print].
  • Getting a handle on RAS-targeted therapies: cysteine directed inhibitors. Huynh MV,Campbell SL. Mini Rev Med Chem. 2016; 16(5)383-90. [Epub ahead of print] PMID: 26423694
  • Molecular mechanism of vinculin activation and nano-scale spatial organization in focal adhesions. Case, LB, Baird, M, Shtengel, G, Campbell, SL, Hess, H, Davidson, MD and Waterman, C.  Nature Cell Biology.  2015 Jul; 17(7):880-92. Doi: 10.1038/ncb3180.
  • Protein-protein interaction analysis by nuclear magnetic resonance spectroscopy. Thompson PM, Beck MR, Campbell SL. Methods Mol Biol. 2015;1278:267-79. PMID:25859955
  • Rac1 modification by an electrophilic 15-deoxy Δ(12,14)-prostaglandin J2 analog. Wall SB, Oh JY, Mitchell L, Laube AH, Campbell SL, Renfrow MB, Landar A. Redox Biol. 2015;4:346-54. PMID:25677088
  • Rho GTPases, oxidation, and cell redox control. Hobbs GA, Zhou B, Cox AD, Campbell SL. Small GTPases. 2014;5(2):e28579. PMID:25658001
  • Redox Regulation of Rac1 by Thiol Oxidation. G A Hobbs, LE Mitchell, ME Arrington, HP Gunawardena, MJ DeCristo, RF Loeser, X Chen, AD Cox and SL Campbell.  Free Radic Biol Med 2014, in press.
  • Mutation-specific RAS oncogenicity explains N-Ras codon 61 selection in melanoma. CE Burd, W Liu, MV Huynh, MA Waqua, JE Gillahan, KS Clark, K Fu, BL Martin, WR Jeck, GP Souroullas, DB Darr, DC Zedek, MJ Miley, BC Baguley, SL Campbell, N.E. Sharpless. Cancer Discov. 2014, in press.
  • Phosphorylation at Y1065 in Vinculin mediates actin bundling, cell spreading, and mechanical responses to force. CE Tolbert, PM Thompson, R Superfine, K Burridge and SL Campbell. Biochemistry. 2014 Aug 21. [Epub ahead of print] PMID:25115937.
  • Rho GTPases, oxidation, and cell redox control. GA Hobbs, B Zhou, AD Cox and SL Campbell. Small GTPases. 2014;5:e28579. doi:10.4161/sgtp.28579. Epub 2014 May 8. PMID:24809833.
  • Identification of a new actin binding surface on vinculin that mediates mechanical cell and focal adhesion properties. PM Thompson, CE Tolbert, K Shen, P Kota, SM Palmer, KM Plevock, A Orlova, VE Galkin, K Burridge, EH Egelman, NV Dokholyan, R Superfine and SL Campbell. Structure, 2014 May 6;22(5):697-706. d10.1016/j.str.2014.03.002. Epub 2014 Mar 27. PMID:24685146. Press release:
  • Copper is required for oncogenic BRAF signaling and tumorigenesis. DC Brady, MS Crowe, ML Turski, GA Hobbs, X Yao, A Chaikuad, S Knapp, K Xiao, SL Campbell, DJ Thiele and CM Counter. 2014. Nature, May 22;509(7501):492-6. doi: 10.1038/nature13180. Epub 2014 Apr 9.
  • Protein-Protein Interaction Analysis by Nuclear Magnetic Resonance Spectroscopy. PM Thompson, MR Beck, SL Campbell. Protein-Protein Interactions. Methods and Applications 2nd Ed. (Fu H., Meyerkord C., Ed.) Methods in Molecular Biology. In press.
  • Biophysical and proteomic characterization strategies for cysteine modifications in ras GTPases. GA Hobbs, HP Gunawardena and SL Campbell. Methods Mol Biol. 2014; 1120:75-96.
  • Differences in the Regulation of K-Ras and H-Ras Isoforms by monoubiquitination. R Baker, EM Wilkerson, K Sumita, DG Isom, AT Sasaki, HG Dohlman, SL Campbell. J Biol Chem. 2013 Dec 27;288(52):36856-62.
  • Site-specific monoubiquitination activates Ras by impeding GTPase-activating protein function. GA Hobbs, RA Baker and SL Campbell.  Small GTPases, 2013 Sep 12;4(3). Epub ahead of print.
  • Vinculin-actin interaction couples actin retrograde flow to focal adhesions, but is dispensable for focal adhesion growth. I Theivessen, PM Thompson, S Berlemont, KM Plevock, SV Plotnikov, A Zemljic-Harpf, RS Ross, MW Davidson, G Danuser, SL Campbell and CM Waterman.  J Cell Biol. 2013 202:163-177. Press release and Video by Journal of Cell Biology’s Biosights.
  • Structure and Function of Palladin’s Actin Binding Domain. MR Beck, RD Dixon, SM Goicoechea, GS Murphy, JG Brungardt, MT Beam, P Srinath, J Patel, J Mohiuddin, CA Otey, SL Campbell, J. Mol. Biol. 2013 425(18):3325-37.
  • Vinculin and metavinculin: differences in interactions with F-actin and oligomerization. PM Thompson, CE Tolbert, SL Campbell. FEBS Lett. 2013 587(8):1220-9.
  • Vinculin Regulation of F-actin Bundle Formation: What Does it Mean for the Cell?  CT Tolbert, K Burridge and SL Campbell.  2013 Cell Adh Migr. Jan 10; 7(2): 219-225.
  • Glutathiolated Ras: Characterization and Implications for Ras Activation. GA Hobbs, MG Bonini, HP Gunawardena, X Chen and SL Campbell.  2013 Free Radic Biol Med. Apr;57:221-9.
  • Site-Specific Monoubiquitination Activates Ras by Impeding GTPase Activating Protein Function. R Baker, SM Lewis, EM Wilkerson, AT Sasaki, LC Cantley, B, Kuhlman, HG Dohlman, SL Campbell. Nat Struct Mol Biol.  Jan; 20(1): 46-52.
  • Research highlight; Baker, R. Identifying the Mechanism by Which Monoubiquitylation Activates Ras. Nature Rev. Mol. Cell Biol. (2013); NCI press release:
  • Redox regulation of Ras and Rho GTPases: mechanism and function. L Mitchell, A Hobbs, A Aghajanian and SL Campbell, Antioxidants Redox Signaling. Antioxid Redox Signal. 2013 18(3)250-8. PMID:22657737.

Lab Contact:

Lab Room: 3100A-B Genetic Medicine
Lab Phone: (919) 966-6781



Filed under: ,