Luc Berthiaume

Luc Berthiaume (Ph.D. University of Sherbrooke)

Professor

Cell Biology, Member of Lipid Biology Research Group
5-55 Medical Sciences Building
Phone: (780) 492-5146
Fax: (780) 492-0450 (fax)
luc.berthiaume@ualberta.ca


Awards

  • CIHR Scholar
  • AHFMR Scholar

Scope of the research programme

Fatty acylation is one of many types of post-translational modification of proteins by lipids which also includes modification by isoprenoids, glycosyl phosphatidyl  inositols, and cholesterol. Fatty acylation, the covalent attachment of long chain fatty acids to proteins, is a critical cellular control mechanism. Indeed, fatty acylation is a very unique protein modification that impacts on virtually every aspect of cellular life including the regulation of membrane targeting, apoptosis, cell proliferation, protein-protein interaction, protein stability and protein secretion. Fatty acylated proteins are surprisingly abundant and form a large and understudied protein family, which is divided into two groups: myristoylation and palmitoylation. It is estimated that at least 5% of nuclear encoded proteins are either myristoylated or palmitoylated and yet little is known about the biology of protein fatty acylation. With the exception of N-myristoyl-transferase 1 (NMT1), again, little is also known about the enzymology of the recently identified fatty acyl transferases.

Many acylated proteins are linked to the disease state. Examples include: Src, Ras and Wnt oncogenes are involved in cancer progression while acylated HIV Gag and GP160 are involved in the HIV life cycle and AIDS. In addition, G-protein coupled receptors are involved in a variety of patho-physiological conditions such as hypertension (e.g. b-adrenergic and vasopressin receptors). Studying fatty acylation is therefore highly clinically relevant. We have focused on cancer and cardiovascular diseases as our pathophysiological models. Together, these account for 60% of all deaths in Canada. For the first time cancer related deaths exceed deaths from cardiovascular diseases and cancer is now the #1 cause of death. Also according to StatsCan, ~14,500 new cases of cancer and 5,800 deaths from cancer occurred in Alberta in 2007. A similar number of Albertans died from cardiovascular diseases. Thus, cancer and cardiovascular research is invaluable for the health of Albertans and Canadians.

My laboratory studies the role of protein fatty acylation across the full spectrum of signal transduction. Simply put, signal transduction is the movement of a signal from outside to inside the cell. It often results in changes in gene expression, which in turn, alters cellular metabolism. More precisely, we study the role of protein fatty acylation in membrane localization as it pertains to the regulation of apoptosis and cell proliferation. Second, we study the involvement of palmitoylation in the regulation of gene expression and enzymatic activity resulting in the fine-tuning of mitochondrial metabolism.

Detection of fatty acylated proteins, chemical biology leading the way

Progress in the study of fatty acylation has been hampered by the lack of rapid detection methods. Until very recently, detection of fatty acylated proteins relied on the tedious and hazardous incorporation of radioactive [3H]-fatty acids into proteins followed by lengthy fluorographic exposures (often months). Subsequently, as a post-doctoral fellow, I was part of team that developed the use of [125I]-iodofatty acids as labels, which reduced exposure time significantly but these were also hazardous and not commercially available. Recent breakthroughs led to major improvements in detection and identification of fatty acylated proteins: the use of the acyl-biotinyl exchange reaction (ABE) and the use of azido- and alkynyl fatty acid analogues now offer rapid, non-radioactive and sensitive new means of detecting fatty acylated proteins.

In collaboration with Drs. Falck (University of Texas Southwestern, Dallas) and Bertozzi (University of California at Berkeley), we developed two direct non-radioactive labeling methods to rapidly detect and isolate fatty acylated proteins from complex cell mixtures that has reduced detection exposure times from months to seconds (~5 million times faster) (29).  The first method takes advantage of the fact that azido-fatty acid analogues are not toxic to cells or animals and can be both directly incorporated into proteins and rapidly detected using fluorescent-, biotinyl-, FLAG- or Myc-phosphine tags using the Staudinger-Bertozzi reaction. We successfully used this method to identify 5 new putative post-translationally myristoylated proteins (29) and 21 palmitoylated rat liver mitochondrial proteins (28,30,34). We also developed an even more sensitive method using the incorporation of w-alkynyl-fatty acid labels into proteins and their capture with azido-biotin using the Copper(I)-catalyzed Alkyne-Azide Cycloaddition commonly known as “click reaction”. Using this latter method, we can detect the myristoylation of endogenous and exogenous myristoylated proteins as well as the palmitoylation of endogenous or exogenous N- or H-Ras in cells in seconds (33), and, for the very first time, in vivo (33).

Past and Current Funding

Three grants typically fund our work:

CIHR: Role of post-translational myristoylation in apoptosis and cancer.

Alberta Cancer Research Institute: Fatty acyl transferases and the onset / progression of cancer.

Heart and Stroke Foundation of Alberta, NWT and Nunavut: Mitochondrial palmitoylation and the regulation of gene expression, enzyme activity and metabolism in the metabolic syndrome.

 


Selected Publications

44*. Dale D.O. Martin, Ryan J. Heit, Megan C. Yap, Michael W. Davidson, Michael R. Hayden and Luc G.  Berthiaume  (2014)  “Identification of a posttranslationally myristoylated autophagy inducing domain released by caspase cleavage of Huntingtin” Human Molec. Genet. 23(12):3166-79. doi: 10.1093/hmg/ddu027. Epub 2014 Jan 23.
(*Cover page of the journal) 

43*. Berthiaume, Luc G. (2013) “Wnt acylation: Seeing is believing” Nature Chemical Biology Published online 24 November 2013 doi:10.1038/nchembio.1414 (*Invited Commentary) 

42*. Emily M. Lynes, Arun Raturi, Marina Shenkman, Carolina Ortiz Sandoval, Megan C. Yap, Jiahui Wu, Aleksandra Janowicz, Nathan Myhill, Matthew D. Benson, Robert E. Campbell, Luc G. Berthiaume, Gerardo Z. Lederkremer and Thomas Simmen  “Palmitoylation is the Switch that Assigns Calnexin to Quality Control or ER Calcium Signaling” Journal Cell Science (in press, 10 July 2013, Epub ahead of print) *Highlighted as featured paper in JCS  

41. Gu HM, Li G, Gao X, Berthiaume LG, Zhang DW (2013) “Characterization of palmitoylation of ATP binding cassette transporter G1: Effect on protein trafficking and function. Biochim Biophys Acta. 1831:1067-1078. 

40. Perinpanayagam MA, Beauchamp E, Martin DD, Sim JY, Yap MC, Berthiaume LG (2013) “Regulation of co- and post-translational myristoylation of proteins during apoptosis: interplay of N-myristoyltransferases and caspases” FASEB J. 27: 811-21              

39. Dale D.O. Martin, Chrisselle Y. Ahpin, Ryan J. Heit, Maneka A. Perinpanayagam, Megan C. Yap, Richard A. Veldhoen, Ing Swie Goping and Luc G. Berthiaume (2012) “Tandem reporter assay for myristoylated proteins post-translationally (TRAMPP) identifies novel substrates for post-translational myristoylation: PKC epsilon; a case study” FASEB J 26:13-28

38. Emily Lynes, Michael Bui, Megan C. Yap, Lars Ellgaard, Luc G. Berthiaume and Thomas Simmen (2011) “Palmitoylation Mediates the Enrichment of TMX and Calnexin on the Mitochondria-Associated Membrane (MAM)” EMBO J., 31:457-70                                                                                                                                                     

36. Martin, D.D.O. , Beauchamp, E. and Berthiaume, L.G. (2011) “Post-translational myristoylation: fat matters in cellular life and death” Biochimie  93, 18-31

34. Morris A. Kostiuk, Bernd O. Keller and Luc G. Berthiaume. (2010) “Palmitoylation of HMG-CoA synthase promotes its interaction with PPARa and enhances transcription from the HMG-CoA synthase PPRE: a novel co-activation mechanism”  (In press. FASEB J.)

33. Megan C. Yap*#, Morris A. Kostiuk*, Dale D. O. Martin, Maneka A. Perinpanayagam, Pieter G. Hak, Anjaiah Siddam, Janaki R. Majjigapu, Gurram Rajaiah, Bernd O. Keller, Jennifer A. Prescher, Peng Wu, Carolyn R. Bertozzi, John R. Falck and Luc G. Berthiaume (2010) “Detecting the palmitoylation of endogenous proteins with w-alkynyl-palmitate in vitro, in cultured cells and in vivo using click chemistry: H- and N-Ras as a case study” J. Lipid Res. 51, 1566-1580)
(* these authors contributed equally, # our technician)

31. Meyer-Schaller N, Chou YC, Sumara I, Martin DD, Kurz T, Katheder N, Hofmann K, Berthiaume LG, Sicheri F, Peter M. (2009) “The human Dcn1-like protein DCNL3 promotes Cul3 neddylation at membranes”. Proc. Natl. Acad. Sci. U. S. A. 106:12365-70.

30. Kostiuk, M.A, Bernd O. Keller and Berthiaume, L.G. (2009) “Non-radioactive detection of palmitoylated mitochondrial proteins using an azido-palmitate analogue” Methods in Enzymology 457:149-165

29. Martin, Dale D.O., Vilas, Gonzalo L., Prescher, Jennifer A., Rajaiah, Gurram, Falck, John R., Bertozzi, Carolyn R.,  Berthiaume, Luc G. (2008) “Rapid detection, discovery and identification of post-translationally myristoylated proteins during apoptosis using a bioorthogonal azidomyristate analogue.” FASEB J. 22, 797-806

28. Morris A. Kostiuk, Maria M. Corvi, Bernd O. Keller, Greg Plummer, Jennifer A. Prescher, Matthew J. Hangauer, Carolyn R. Bertozzi, Gurram Rajaiah, John R. Falck and Luc G. Berthiaume (2008) “Identification of palmitoylated mitochondrial proteins using a bio-orthogonal azido-palmitate analogue” FASEB J. 22, 721-732

27. M. Sariahmetoglu, B.D. Crawford, H. Leon, J. Sawicka, L. Li, B.J. Ballermann, C. Holmes, L.G. Berthiaume, A. Holt, G. Sawicki and R. Schulz (2007) "Matrix metalloprotease-2 is regulated by phosphorylation" FASEB J., 21, 2486-2495

26*. Gonzalo L Vilas, Maria M Corvi, Greg J Plummer, Andrea M Seime, Gareth R Lambkin and Luc G Berthiaume (2006) “Post-translational myristoylation of caspase-activated PAK2 potentiates late apoptotic events” Proc. Natl. Acad. Sci. U.S.A. 103, 6542-6547.

*Cited in the Faculty of 1000  

 

N.B. The names of the Berthiaume lab trainees are underlined.