New Research Discoveries: Prion proteins and neuron degeneration

A new paper in eLife from the Harris lab has uncovered a novel function for different domains of the prion protein. Bei Wu, an Instructor in the laboratory was lead author.

Prion diseases, or transmissible spongiform encephalopathies, comprise a group of fatal neurodegenerative disorders in humans and animals for which there are no effective treatments or cures. These diseases are caused by refolding of the cellular prion protein (PrPC) into an infectious isoform (PrPSc) that catalytically templates its abnormal conformation onto additional molecules of PrPC. A similar, prion-like process may play a role in other neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases and tauopathies, which are due to protein misfolding and aggregation. Here, using a combination of electrophysiological, cellular, and biophysical techniques, we show that the flexible, N-terminal domain of PrPC functions as a powerful toxicity-transducing effector whose activity is tightly regulated in cis by the globular C-terminal domain. Ligands binding to the N-terminal domain abolish the spontaneous ionic currents associated with neurotoxic mutants of PrP, and the isolated N-terminal domain induces currents when expressed in the absence of the C-terminal domain. Anti-PrP antibodies targeting epitopes in the C-terminal domain induce currents, and cause degeneration of dendrites on murine hippocampal neurons, effects that entirely dependent on the effector function of the N-terminus. NMR experiments demonstrate intramolecular docking between N- and C-terminal domains of PrPC, revealing a novel auto-inhibitory mechanism that regulates the functional activity of PrPC.

Welcome New Faculty

By mlayneJune 6th, 2017in Departmental News

We are delighted to announce the recruitment of 2 new faculty members who will be joining the Department on July 1, 2017. The search that identified these faculty members was a joint effort between the Biochemistry Department and the Genome Science Institute.

Nelson Lau, Ph.D., will be appointed as an Associate Professor. His laboratory will be located on the second floor of the K Bldg. Nelson has a long-standing involvement in the RNA field. He completed his Ph.D. at MIT in 2004 with Dr. David Bartel, a pioneer in the then nascent field of microRNAs. As part of his thesis work, he cloned the first large collection of microRNAs from C. elegans, work that was awarded the Newcomb Cleveland prize from the AAAS in 2002. From 2004-2009, Nelson was a Helen Hay Whitney Foundation fellow in the laboratory of Dr. Robert Kingston at Massachusetts General Hospital/Harvard Medical School. During his fellowship, he was the first to describe the piRNA complex from rats and mice, a discovery that was a runner-up for Science magazine’s 2006 Breakthrough of the Year. In 2009, Nelson was recruited as an Assistant Professor to the Department of Biology at Brandeis University. There, he established a vibrant and productive research program focused on regulation of the genome by transposon landscapes and the Piwi/piRNA pathway. His laboratory produced a number of important advances, including: (1) Establishment of new links between the Piwi pathway, transposon landscapes, and long non-coding RNAs; (2) Discovery of eutherian-mammal conserved genic piRNA clusters; (3) Development of new technical methods to study the RNAi pathway. Nelson’s interests complement those of Alla Grishok and Daniel Cifuentes, further adding to our department’s strengths in RNA biology. Nelson also adds two new model organisms to our department: Drosophila and Xenopus tropicalis.

 

Andrew Emili, Ph.D., will be a Professor, with dual appointments in the Dept. of Biochemistry and in the Department of Biology on the Charles River Campus. He will establish a Center for Network Systems Biology, which will be located on the third floor of the K Bldg. in space that is currently being renovated for this purpose. Andrew was recruited through the Provost’s Senior Faculty Hiring Initiative, aimed at attracting world-class researchers to Boston University who will bridge the two campuses. He is currently a Professor in the Donnelly Centre for Cellular and Biomolecular Research and the Department of Molecular Genetics at the University of Toronto, where he has been located since 2000. He received his Ph.D. (1997) in Molecular and Medical Genetics from the University of Toronto, and was a postdoctoral fellow (1997-2000) at the Fred Hutchison Cancer Research Center in Seattle working with John Yates. Andrew is an international leader in the analysis of protein interaction networks. He uses systems-level analysis, bioinformatics and especially proteomics to answer large-scale questions about protein-protein interaction networks in cells. Andrew’s publication list includes high profile, proteome-wide studies of protein complexes in yeast, E. coli, and human cells, and his group has documented hundreds of novel complexes linked to development and disease. Andrew’s center will synergize with the Center for Biomedical Mass Spectrometry, directed by Cathy Costello and Joe Zaia, further establishing our dept. as a leader in applications of mass spectrometry to biological problems.

Dahoud Breast Cancer Pilot Awards

Congratulations to several Biochemistry faculty who were recently awarded Dahoud Breast Cancer Pilot Awards.

Alla Grishok, PhD, Associate Professor of Biochemistry, Dafne Cardamone, PhD, Instructor, and Catherine Costello, PhD, Director of Center for Biomedical Mass Spectrometry, will study regulation of cancer-promoting Myc protein using a model metastatic breast cancer cell line. Myc binds DNA and activates a large network of genes that together transform normal cells into cancer cells. Myc activity is elevated in most human cancers and is especially relevant for Myc-driven triple (estrogen, progesterone and Her2) negative breast cancer. Dr. Grishok and colleagues will investigate new mechanisms that increase Myc protein activity: 1) adding specific sugar residues, and 2) protein truncation. New compounds that directly inhibit Myc or inhibit enzymes that activate Myc could be developed into new cancer therapies.
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Xaralabos Varelas, PhD, Associate Professor of Biochemistry and Stefano Monti, PhD, Associate Professor of Medicine and Biostatistics, will study the causes of aggressive triple negative breast cancers. The team will determine how abnormal signaling networks drive gene expression changes that lead to aggressive breast cancers and then categorize subsets of aggressive breast cancers, thereby better targeting the most effective treatments based on the genes expressed in the tumor.

Mikel Garcia-Marcos Awarded Grunebaum Fellowship

Mikel Garcia-Marcos has been selected as the Karin Grunebaum Cancer Research Fellow for a second year in a row.  The Grunebaum Faculty Research Fellowship is a BUSM annual faculty award that provides $25,000 in total funds to a selected faculty member for a period of one year.  Several Faculty members of our Department, including Bob Varelas and Valentina Perissi, have been awarded this fellowship in the past.  Dr. Garcia-Marcos plans to work on developing a novel therapeutic strategy against cancer metastasis that targets an unconventional mechanism of heterotrimeric G protein activation not mediated by surface receptors (GPCRs).

Cathy Costello receives prestigious mass spectrometry award

Cathy Costello was recently awarded the 2017 Award for a Distinguished Contribution in Mass Spectrometry by the American Society for Mass Spectrometry. This award recognizes a singular significant achievement and was for her pioneering contributions to the development of tandem mass spectrometry of glycans and glycoconjugates. Addtional details of the award can be found on the ASMS web page. Congratulations Cathy!

 

Molecular mechanism of G protein activation by GIV, a protein that promotes metastasis

The insufficient mechanistic information on metastasis has precluded the development of efficient therapeutics for it. The Gα-Interacting, Vesicle-associtated  (GIV) protein is emerging as a very promising candidate to become one of the “master regulators” of metastasis and as such, its characterization may open new avenues for therapeutic intervention.

By a combination of biochemical and structural techniques, including NMR, a team of researchers have uncovered the molecular mechanism behind GIV binding and activation of a G protein. G proteins are components of the communication system the body uses to sense hormones in the bloodstream and send the corresponding messages to cells.

The results show that the mode of action of GIV differs from the well known GPCR proteins, because it binds to a different region. Molecular modelling and NMR data inform about the protein-protein interface and show that GIV binds to a cavity on the surface of the G protein. These results suggest and allosteric regulation mechanism as conformational changes in one site propagate to another distant site in the molecule.

The work has been the result of a close collaboration between the group of Mikel García-Marcos  at Boston University, and the group of Francisco J Blanco at CIC bioGUNE, and has appeared in the journal Nature Communications.

 The synergy between the two teams, and the participation or researchers from IRB Barcelona, Cornell University, and University of Glasgow has made it possible to uncover this novel mode of action of a G protein regulator. Multidisciplinary studies of this kind are key to characterize the complex biological processes relevant in biomedical cancer research.

Reference: Molecular mechanism of Gαi activation by non-GPCR proteins with a Gα-Binding and Activating motif. A Ibáñez de Opakua, K Parag-Sharma, V DiGiacomo, N Merino, A Leyme, A Marivin, M Villate, LT Nguyen, MA de la Cruz-Morcillo, JB Blanco-Canosa, S Ramachandran, George S Baillie, RA Cerione, FJ Blanco, M Garcia-Marcos (2017) Nature Commun 8, 13935.

Congratulations Graduates

The Department of Biochemistry would like to congratulate our recent graduates. Receiving a PhD in Biochemistry:Erin Bove-Fenderson, Carly Cederquist, Anthony Jay, Kshitij Khatri, Chun Shao, and Aleksander Szymaniak. Receiving a dual MD and PhD degree in biochemistry: Kelsey Derricks. Receiving a MA in Biochemistry: Wajeeha Qureshi.

Congratulations to all!

 

 

Biochemistry Retreat 2017

Please note the RSVP deadline has passed. If you have any questions please contact Erika. For poster title submissions please use this form: Poster Title

The 2017 Biochemistry Retreatwill be an all day event on Thompson’s Island in Boston Harbor on Friday June 16th.

We hope all members of Biochemistry labs are able to attend and like last year we are looking forward to a great day.

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2017 Retreat Committee:

Matt, Bob, Valentina, Erika, Jean, Rekha, Yang

 

New Research from Perissi Lab: GPS2 and insulin signaling

By mlayneFebruary 14th, 2017in Departmental News, Research News

A new study from the Perissi lab has revealed an unexpected layer of regulation in the insulin signaling cascade based on the opposing actions of the ubiquitin conjugating enzyme Ubc13 and its inhibitor GPS2. The work, recently published in Molecular Metabolism, shows that Ubc13-mediated ubiquitination of the AKT/PKB kinase is required for its phosphorylation and activation in the insulin signaling cascade. Conversely, loss of GPS2-mediated inhibition of Ubc13 activity promotes sustained insulin signaling both in vitro, in 3T3-L1 adipocytes, and in vivo in the adipose tissue of GPS2-AKO mice. Dr. Valentina Perissi and Carly Cederquist, the graduate student who led the project, discuss their finding in the 60 Second Metabolist video (below)