Molecular biology

Our laboratory is both experimental and computational. We use next-generation sequencing technologies to measure genome-wide molecular phenotypes. By leveraging the interconnected relationships between DNA sequence, transcription factor binding, chromatin modification, and gene expression, we study how cells achieve context-appropriate expression patterns and signal responsiveness. Lab Website: www.romanoskilab.com Keywords: Genetics, Genomics, Vascular Biology, Bioinformatics

All viruses hijack host cell machinery to facilitate their replication. Producing infectious viral progeny relies on host cell metabolic pathways to provide energy and building blocks such as nucleotides, amino acids, and lipids. I am interested in investigating the molecular remodeling of cellular metabolic and lipid environments by viruses. The overall goal of my research in dissecting the complex virus-host metabolism interactions is to guide the development of novel antiviral therapies. Keywords: Infectious Disease, Virology, Metabolism, Lipidomics

William Montfort, PhD, determines the atomic structures of proteins and seeks to understand how protein structure gives rise to protein function – both in vitro and in living cells. At their heart, the problems have a fundamental structure-function question, but also address questions of importance to human health. Approaches include X-ray crystallography, rapid kinetic measurements, spectroscopy, theory, protein expression, drug discovery, molecular genetics and related techniques.Dr. Montfort is particularly interested in nitric oxide signaling mechanisms. Nitric oxide (NO) is a small reactive molecule produced by all higher organisms for the regulation of an immensely varied physiology, including blood pressure regulation, memory formation, tissue development and programmed cell death. He is interested in two NO signaling mechanisms: binding of NO to heme and the nitrosylation (nitrosation) of cysteines. NO, produced by NO synthase, binds to soluble guanylate cyclase (sGC) at a ferrous heme center, either in the same cell or in nearby cells. Binding leads to conformational changes in heme and protein, and to induction of the protein’s catalytic function and the production cGMP. NO can also react with cysteine residues in proteins, giving rise to S-nitroso (SNO) groups that can alter protein function. He continues to study the mechanistic details surrounding cGMP and SNO production, and the signaling consequences of their formation.For reversible Fe-NO chemistry, Dr. Montfort is studying soluble guanylate cyclase and the nitrophorins, a family of NO transport proteins from blood-sucking insects. Our crystal structures of nitrophorin 4 extend to resolutions beyond 0.9 angstroms, allowing us to view hydrogens, multiple residue conformations and subtle changes in heme deformation. For reversible SNO chemistry, he is studying thioredoxin, glutathione S-nitroso reductase (GSNOR) and also sGC. For regulation in the cell, Dr. Montfort and his group have constructed a model cell system based on a human fibrosarcoma called HT-1080, where sGC, NO synthase, thioredoxin and GSNOR can be manipulated in a functional cellular environment. With these tools, they are exploring the molecular details of NO signaling and whole-cell physiology, and undertaking a program of drug discovery for NO-dependent diseases. Keywords: Structural Biology, Drug Discovery, Cancer, Cardiovascular Disease

Membrane proteins play a number of critical biochemical roles and make up the majority of drug targets. Despite their importance, membrane proteins remain challenging systems for analysis due to their amphipathic nature and low expression levels. Moreover, the lipid bilayer can play an important but largely unexplored role in regulating membrane protein structure and function. New analytical and biochemical methods are necessary to better understand and design drugs to target membrane proteins.

Public Relevance Statement: Can you imagine having a mouthful of canker sores and cavities? Thousands of head and neck cancer patients suffer these consequences from radiation treatment. The Limesand lab works to prevent these side effects thereby improving patients' quality of life. Clinical Relevance: Radiation therapy for head and neck cancer causes adverse secondary side effects in the normal salivary gland including xerostomia, oral mucositis, malnutrition, and increase oral infections. Although improvements have been made in targeting radiation treatment to the tumor, the salivary glands are often in close proximity to the treatment site. The significant destruction of the oral cavity following radiation therapy results in diminished quality of life and in some cases interruptions in cancer treatment schedules. Research Interests: My research program has its foundation in radiation-induced gland dysfunction; mechanisms of damage, clinical prevention measures, and restoration therapies. Evidence suggests that salivary acinar function is compromised due to apoptosis induced by these treatments and temporary suppression of apoptotic events in salivary glands would have significant benefits to oral health. We utilize a number of techniques in my laboratory including: genetically engineered mouse models, real-time RT/PCR, immunoblotting, immunohistochemistry, primary cultures, siRNA transfections, irradiation, and procedures to quantitate salivary gland physiology. Current project areas: 1. Radiation-induced apoptosis 2. Mechanisms of preserving salivary gland function 3. Identifying the radiosensitivity of salivary gland progenitor cells 4. Restoration of salivary gland function 5. Role of autophagy in radiation-induced loss of function

Walter T. Klimecki, DVM, PhD, is an Associate Professor in the Department of Pharmacology and Toxicology in the College of Pharmacy at the University of Arizona. Dr. Klimecki holds joint appointments in the College of Medicine, the College of Public Health, and the Arizona Respiratory Center. He is a Full Member of the Southwest Environmental Health Sciences Center (SWEHSC) where, together with BIO5 director Martinez and BIO5 Statistics Consulting Service director Billheimer, he leads the Integrative Health Sciences (IHS) Center at SWEHSC. The IHS is a translational research support core at SWEHSC, focused on lowering the “activation energy” for translational research.Dr. Klimecki’s research focuses on the toxicology of metals in the environment, an issue particularly relevant in our mining-intensive state. His research work has encompassed a wide range of experimental approaches, from epidemiological studies of arsenic-exposed human populations, to laboratory models including cell culture and rodents. Using cutting edge genetics tools, Dr. Klimecki’s group recently published the first report of an association between human ancestry and response to environmental toxicants. In this provocative work, his group found that individuals whose genomes were comprised of DNA with its origins in the indigenous American populations processed ingested arsenic in a less harmful manner than did individuals whose genomes had their origins in Europe. Using laboratory models his group made ground-breaking discoveries of the impact of arsenic exposure on a process known as autophagy, in which cells digest parts of their own machinery in a sort of “cash for clunkers” arrangement. The ability of arsenic to perturb this process is only now being appreciated by the toxicology community, thanks to the work of the Klimecki Lab. Dr. Klimecki was recently elected as a Vice President-elect to the Metals Specialty Section of the Society of Toxicology, the preeminent scientific toxicology organization in the world. Dr. Klimecki’s research is highly collaborative: his grants and publications have included many BIO5 members, including BIO5 director Fernando Martinez, and BIO5 members Donata Vercelli, Dean Billheimer, and Marilyn Halonen.

Minkyu Kim, Ph.D., is an Assistant Professor in the Department of Materials Science and Engineering and the Department of Biomedical Engineering at the University of Arizona. He received a M.S. (2006) in Biomedical Engineering and a Ph.D. (2011) in Mechanical engineering and Materials Science at Duke University. During his Ph.D., he worked in the Single-Molecule Force Spectroscopy group led by Prof. Marszalek. He was a postdoc at MIT from 2012 to 2016, and worked in the Bioinspired and Biofunctional Polymers group led by Prof. Olsen. Dr. Kim’s research is focused on the design and development of biopolymer-based functional materials for targeted applications in healthcare and for national defense. Based on his diverse research experiences in the areas of biopolymer nanomechanics, polymer physics and self-assembly, biomolecular engineering and soft materials, his group is currently developing (a) mechanically responsive soft materials that mimic reversible deformability of red blood cell and that can be utilized as targeted drug delivery vehicles for the early treatment of atherosclerosis and (b) nuclear membrane inspired biopolymer materials that selectively filter and neutralize a broad range of bacteria, fungi and viruses for pharmaceutical, food safety, water decontamination and defense applications. In addition to biomaterial development to mitigate atherosclerosis and infectious diseases, Dr. Kim is also interested in addressing how bioinspired design and biosynthesis can be used for the preparation of novel functional materials, how the nanomechanics of folded biopolymers and artificially engineered hyperbranched biopolymer structures can be translated into the mechanics of macromolecular materials that provide new insight into polymer science, and how protein sequences can control parameters that regulate the functional properties of polymeric materials. Lab Website: http://kim.lab.arizona.edu

The long-term goal of research in my lab is to understand the molecular mechanisms of muscle contraction. I am especially interested in how contractile proteins of muscle sarcomeres regulate the force and speed of contraction in the heart. The question is important from both basic science and clinical perspectives because mutations in sarcomere proteins of muscle are a leading cause of hypertrophic cardiomyopathy (HCM), the most common cause of sudden cardiac death in the young and a prevalent cause of heart failure in adults. Myosin binding protein-C (MyBP-C) is a muscle regulatory protein that speeds actomyosin cycling kinetics in response to adrenaline (b-adrenergic stimuli) and is one of the two most commonly affected proteins linked to HCM. Currently, the major research focus in my lab is understanding the mechanisms by which cMyBP-C regulates contractile speed and mechanisms by which mutations in cMyBP-C cause disease. In pursuing these interests I have established a variety of approaches to investigate muscle contraction at molecular, cellular, and whole animal levels. Methods include single molecule atomic force microscopy (AFM), mechanical force measurements in permeabilized muscle cells, in vitro motility assays, biochemical enzyme and binding assays, immunofluorescent imaging, knockout/transgenic animal models and the development of a natural large animal model of HCM.

Michael Hammer is a Research Scientist in the Division of Biotechnology at the University of Arizona with appointments in the Department of Neurology, Ecology and Evolutionary Biology, Bio5, the School of Anthropology, the University of Arizona Cancer Center, and the Steele Children's Research Center. Currently Dr. Hammer is interested in the use of the latest DNA sequencing technology to infer the underlying genetic architecture of neurodevelopmental diseases. Since 1991 Dr. Hammer has directed of the University of Arizona Genetics Core (UAGC), a facility that provides training and molecular biology services to University and biotechnology communities at large. After receiving his Ph.D. in Genetics at the University of California at Berkeley in 1984, he performed post-doctoral research at Princeton and Harvard. Over the past two decades, Dr. Hammer has headed a productive research lab in human evolutionary genetics, resulting in over 100 published articles documenting the African origin of human diversity, interbreeding between modern humans and archaic forms of the genus Homo, and genome diversity in the great apes. His lab and the UAGC were early adopters of next generation sequencing (NGS) technology and the application of whole genome analysis in humans, and his lab has been a key player in the Gibbon and Baboon Genome Projects, as well as a consortium that has analyzed the genomes of over 100 Great Apes (GAPE Project). In the past 3 years, Dr. Hammer's research team has succesfully employed NGS methods to identify molecular lesions causing neurodevelopmental disorders in undiagnosed children. This has led to the publication of articles identifying pathogenic variants associated with early onset epileptic encephalopathies. His lab is also currently pursuing studies to identify modifier genes that alter the expression of major genes and how they contribute to phenotypic heterogeneity in Mendelian disorders.

Hendrikus Granzier, PhD, studies the mechanisms whereby the giant filamentous protein titin (the largest protein known) influence muscle structure and function. His lab has shown that titin functions as a molecular spring that mediates acute responses to changing pathophysiological states of the heart. They also study the role of titin in cardiac disease, using mouse models with specific modifications in the titin gene, including deciphering the mechanisms that are responsible for gender differences in diastolic dysfunction. An additional focus of Dr. Granzier’s lab is on nebulin, a major muscle protein that causes a severe skeletal muscle disease in humans. Based on previous work, they hypothesize that nebulin is a determinant of calcium sensitivity of contractile force. To test this and other concepts, he uses a nebulin knockout approach in the mouse. Research is multi-faceted and uses cutting-edge techniques at levels ranging across the single molecule, single cell, muscle, and the intact heart. His research group is diverse and has brought together individuals from several continents with expertise ranging from physics and chemistry to cell biology and physiology.