The goal of my laboratory's research is to understand how fatty acylation influences the structure and function of membrane-bound and secreted signaling proteins. Our focus is on the Src family tyrosine protein kinases and Hedgehog proteins.
My laboratory has established in vitro systems to study the biosynthesis, fatty acylation, and membrane insertion of Src kinases. We identified a novel membrane-binding motif within the Src protein consisting of myristate plus a cluster of basic residues. Membrane association results from synergism provided by hydrophobic insertion of myristate into the lipid bilayer and electrostatic interaction of the positively charged amino acids with negatively charged head groups of acidic membrane phospholipids. This “myristate + basic” motif is also found in the Gag proteins of many retroviruses. Our laboratory showed that the myristate + basic domain mediates plasma membrane targeting of HIV-1 Gag, thereby allowing Gag to function in the formation and budding of virions.
We are currently focusing our efforts on signaling proteins modified by the 16-carbon fatty acid palmitate. We have shown that several Src-related proteins are dually fatty acylated with both myristate and palmitate. The palmitylation reaction is dynamic and reversible, and regulates the ability of Src family members to bind to membranes and participate in signaling. We have defined the molecular mechanisms whereby dual fatty acylation mediates intracellular protein trafficking, targeting to plasma membrane rafts, and intracellular signal transduction.
Our laboratory's efforts have recently expanded to explore the mechanism of palmitoylation of secreted morphogens such as Hedgehog proteins and Wnt proteins. We have established assays for monitoring palmitoylation of Sonic hedgehog (Shh) and have purified and characterized Hedgehog acyltransferase (Hhat), the enzyme that catalyzes attachment of palmitate to Shh. Studies of Hhat enzymatic mechanism and membrane topology are currently underway. In addition, we have exploited high throughput screening to identify Hhat inhibitors. These inhibitors are being tested for their ability to block the growth of cancer cells that are dependent on Shh signaling.
Petrova E, Rios-Esteves J, Ouerfelli O, Glickman JF, Resh MD. Inhibitors of Hedgehog acyltransferase block Sonic Hedgehog signaling. Nat Chem Biol. 2013 Apr;9(4):247-9. doi: 10.1038/nchembio.1184. Epub 2013 Feb 17.
Resh MD. Targeting protein lipidation in disease. Trends Mol Med. 2012 Apr;18(4):206-14. doi: 10.1016/j.molmed.2012.01.007. Epub 2012 Feb 17.
Buglino JA, Resh MD. Hhat is a palmitoylacyltransferase with specificity for N-palmitoylation of Sonic Hedgehog. J Biol Chem. 2008 Aug 8;283(32):22076-88. doi: 10.1074/jbc.M803901200. Epub 2008 Jun 4.
Resh MD. Palmitoylation of ligands, receptors, and intracellular signaling molecules. Sci STKE. 2006 Oct 31;2006(359):re14.
Resh MD. Trafficking and signaling by fatty-acylated and prenylated proteins. Nat Chem Biol. 2006 Nov;2(11):584-90.
Excellence in Teaching and Mentoring Award, Weill Cornell Graduate School (2009)
Established Scientist, American Heart Association (1994-1999)
Pew Scholar in the Biomedical Sciences, Pew Charitable Trusts (1987-1991)
Discovery of the “”two-signal hypothesis”” for binding of myristoylated proteins to membranes
Discovery of a myristoyl switch mechanism for membrane binding of HIV-1 Gag
First to establish Hedgehog acyltransferase as a bona fide palmitoyl acyltransferase for Hedgehog proteins
Discovery of the first-in-class hedgehog palmitoylation inhibitor