William Skach, MD
CELLULAR AND BIOCHEMICAL BASIS OF HUMAN PROTEIN FOLDING DISORDERS: Pathogenesis of Cystic Fibrosis, Aquaporin biogenesis, Membrane protein folding.
Human protein folding disorders comprise a group of diverse clinical diseases that involve every organ system. Despite this diversity, they share a common molecular pathology in which inherited mutations cause structural abnormalities that are recognized by cellular quality control machinery. For example, cystic fibrosis is an autosomal recessive disease in which the mutant CFTR chloride channel fails to fold properly, is rapidly ubiquitinated in the endoplasmic reticulum (ER), and degraded by the 26S proteasome via a process known as ER Associated Degradation (ERAD). Lack of CFTR in the lung leads to mucus dehydration, recurrent infection, inflammation, and ultimately death. Similarly, mutations in aquaporin 2 disrupt folding of a key water channel in the kidney, but in this case the outcome is a severe life-threatening urinary concentration defect. Our group is investigating three basic themes in the pathogenesis of these disorders: 1) How do proteins acquire secondary and tertiary structure cotranslationally as they are synthesized by the ribosome? 2) How do cellular chaperones of the ER and cytosol facilitate membrane protein folding? 3) How are misfolded proteins recognized by quality control machinery, extracted from the ER membrane, and delivered to the ubiquitin-proteasome system?
Our experimental strategies involve a combination of cell biological, biochemical, and biophysical approaches. Proteins are typically expressed from engineered DNA templates in cell free systems that reconstitute early folding, processing and degradation events. Synthetic amino-acyl tRNAs are then used toincorporate non-native amino acids and thereby define the molecular environment of these nascent polypeptides using native and denaturing PAGE, photocrosslinking, fluorescence resonance energy transfer (FRET), fluorescence quenching and other biochemical techniques. The long term goal of our work is to define novel pathways for membrane protein folding, identify biogenesis events that are disrupted by disease-related mutations, and understand how these defects are corrected by novel, clinical drug candidates.
Dr. Skach is accepting rotation students for 2011-2012.
1979.B.S.Biochemistry & Biophysics, Agronomic Crop Science. Oregon Sate University. Biochemistry
1983.M.D. Harvard Medical School
1983-1991.Clinical Training. Internal Medicine, Hematology/Oncology, University of California San Francisco.
1990-1994.Postdoctoral Training. Cancer Research Institute and Department of Physiology, University of California San Francisco,
1988. Physician and Instructor, Freedom Medicine. Peshawar, Pakistan
1994-1998.Assistant Professor of Molecular and Cellular Engineering, University of Pennsylvania
1998-2005.Associate Professor of Medicine, Cell and Developmental Biology, and Physiology & Pharmacology, Oregon Health & Science University
2005-present.Professor of Biochemistry & Molecular Biology, Oregon Health & Science University
Selected Recent Publications
Devaraneni P., Conti, B., Matsumura, Y., Yang, Z., Johnson, A., Skach, W. Stepwise Insertion and Inversion of a Type II Signal Anchor Sequence in the Ribosome-Sec61 Translocon Complex. Cell. 146:134-47,2011.
Matsumura, Y., David, L., Skach, W. Role of Hsc70 Binding Cycle in CFTR Folding and Endoplasmic Reticulum Associated-Degradation. Mol Biol Cell. Jun 22, 2011.
Khushoo A, Yang Z, Johnson A, Skach W. Ligand-Driven Vectorial Folding of Ribosome-Bound Human CFTR NBD1. Molecular Cell. 41:682-92, 2011.
Gubbens J, Kim SJ, Yang Z, Johnson AE, Skach W. In vitro incorporation of non-natural amino acids into protein using tRNA(Cys)-derived opal, ochre, and amber suppressor tRNAs.RNA.16:1660-1672, 2010
Crane JM, Van Hoek AN, Skach W, Verkman AS.Aquaporin-4 dynamics in orthogonal arrays in live cells visualized by quantum dot single particle tracking. Mol Biol Cell. Aug;19:3369-78, 2008.
Buck, T., Wagner, J., Grund, S., Skach, W. A novel tripartite structural motif involved in aquaporin topogenesis, monomer folding, and tetramerization. Nature Struct. Mol. Biol. 14:762-769, 2007
Brodsky, J., Skach, W. Protein Folding and Quality Control in the Endoplasmic Reticulum: Recent Lessons from Yeast and Mammalian Cell Systems. Current Opinion in Cell Biology. 2011.
Skach W. The expanding role of the ER translocon in membrane protein folding. J. Cell. Biol. 1179:333-1335, 2007
Skach, W. CFTR: New members join the fold. Cell. 127:673-675, 2006Lab web page
Link to PubMed Listing
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