Elevation of O-GlcNAc levels modulates numerous pathways in a manner consistent with increased cell survival, including the expression of heat shock proteins. The Zachara Lab's goal is to understand the O-GlcNAc regulated stress response, how this can be manipulated to improve patient outcome and how this response is misregulated in disease.

Research in the Michael Matunis Lab focuses on the SUMO family of small ubiquitin-related proteins. We study the covalent conjugation of SUMOs to other cellular proteins, which regulates numerous processes needed for cell growth and differentiation, and which, when defective, can lead to conditions such as cancer, neurodegenerative disease and diabetes.

Research in the Shigeki Watanabe Lab focuses on the cellular and molecular characterizations of rapid changes that occur during synaptic plasticity. Our team is working to determine the composition and distribution of proteins and lipids in the synapse as well as understand how the activity alters their distribution. Ultimately, we seek to discover how the misregulation of protein and lipid compositions lead to synaptic dysfunction. Our studies make use of cutting-edge electron microscopy techniques in combination with biochemical and molecular approaches.

The Kalina Hristova Lab investigates the structure and assembly of biological membranes. Our team conducts research on the structural and thermodynamic principles that enable membrane protein folding and signal transduction across biological membranes. Part of our work has involved developing new tools to study the structure of thermally disordered fluid membranes and the energetics of biomolecular interactions in biological membranes. Through our studies, we have established a better understanding of the physical principles behind complex biological processes and the mechanisms of disease development in humans.

The Paul Worley Lab examines the molecular basis of learning and memory. In particular, we cloned a set of immediate early genes (IEGs) that are rapidly transcribed in neurons involved in information processing, and that are essential for long term memory. IEG proteins can directly modify synapses and provide insight into cellular mechanisms that support synapse-specific plasticity.

Research in the Alex Kolodkin Laboratory is focused on understanding how neuronal connectivity is established during development. Our work investigates the function of extrinsic guidance cues and their receptors on axonal guidance, dendritic morphology and synapse formation and function. We have investigated how neural circuits are formed and maintained through the action of guidance cues that include semaphorin proteins, their classical plexin and neuropilin receptors, and also novel receptors. We employ a cross-phylogenetic approach, using both invertebrate and vertebrate model systems, to understand how guidance cues regulate neuronal pathfinding, morphology and synaptogenesis. We also seek to understand how these signals are transduced to cytosolic effectors. Though broad in scope, our interrogation of the roles played by semaphorin guidance cues provides insight into the regulation of neural circuit assembly and function. Our current work includes a relatively new interest in understanding the origins of laminar organization in the central nervous system.

The Advanced Optics Lab uses innovative optical tools, including laser-based nanotechnologies, to understand cell motility and the regulation of cell shape. We pioneered laser-based nanotechnologies, including optical tweezers, nanotracking, and laser-tracking microrheology. Applications range from physics, pharmaceutical delivery by phagocytosis (cell and tissue engineering), bacterial pathogens important in human disease and cell division. Other projects in the lab are related to microscopy, specifically combining fluorescence and electron microscopy to view images of the subcellular structure around proteins.

Our research is focused on understanding the basic mechanisms of programmed cell death in disease pathogenesis. Billions of cells die per day in the human body. Like cell division and differentiation, cell death is also critical for normal development and maintenance of healthy tissues. Apoptosis and other forms of cell death are required for trimming excess, expired and damaged cells. Therefore, many genetically programmed cell suicide pathways have evolved to promote long-term survival of species from yeast to humans. Defective cell death programs cause disease states. Insufficient cell death underlies human cancer and autoimmune disease, while excessive cell death underlies human neurological disorders and aging. Of particular interest to our group are the mechanisms by which Bcl-2 family proteins and other factors regulate programmed cell death, particularly in the nervous system, in cancer and in virus infections. Interestingly, cell death regulators also regulate many other cellular processes prior to a death stimulus, including neuronal activity, mitochondrial dynamics and energetics. We study these unknown mechanisms. We have reported that many insults can trigger cells to activate a cellular death pathway (Nature, 361:739-742, 1993), that several viruses encode proteins to block attempted cell suicide (Proc. Natl. Acad. Sci. 94: 690-694, 1997), that cellular anti-death genes can alter the pathogenesis of virus infections (Nature Med. 5:832-835, 1999) and of genetic diseases (PNAS. 97:13312-7, 2000) reflective of many human disorders. We have shown that anti-apoptotic Bcl-2 family proteins can be converted into killer molecules (Science 278:1966-8, 1997), that Bcl-2 family proteins interact with regulators of caspases and regulators of cell cycle check point activation (Molecular Cell 6:31-40, 2000). In addition, Bcl-2 family proteins have normal physiological roles in regulating mitochondrial fission/fusion and mitochondrial energetics to facilitate neuronal activity in healthy brains.

The CRCIF was established to foster collaborative efforts aimed at elucidating the role of intermediate filaments (IFs) in the heart. Intermediate filaments constitute a class of cytoskeletal proteins in metazoan cells, however, different from actin microfilaments and tubulin microtubules, their function in cardiac cells is poorly understood. Unique from the other two components of the cytoskeleton, IFs are formed by cell type-specific proteins. Desmin is the main component of the IFs in the cardiac myocytes. We measured the consistent induction of desmin post-translational modifications (PTMs, such as phosphorylation, etc.) in various clinical and experimental models of heart failure. Therefore, one of our main focuses is to determine the contribution of desmin PTMs to the development of heart failure in different animal and clinical models. Active Projects: • Quantification of desmin PTM-forms in different forms of heart failure at the peptide level using mass spectrometry • Functional assessment of the role of desmin PTMs in heart failure development using single site mutagenesis and biophysical methods • Molecular characterization of desmin preamyloid oligomers using mass spectrometry, in vitro and in vivo imaging • Assessment of the diagnostic and pharmacological value of desmin PTMs in heart failure development

The Johns Hopkins Center for Epithelial Disorders focuses on research into the physiology and pathophysiology of epithelial cells (cells that line the cavities and interior surfaces of the body) of the gastrointestinal (GI) tract, liver, pancreas and kidney. Specifically, the center’s research seeks to: -Understand the mechanisms regulating the activity of transport proteins (including channels) of epithelial cells Characterize the mechanisms by which polarity of epithelial cells are maintained -Investigate the mechanisms controlling transcription of epithelial-specific genes Understand the pathophysiological basis of GI and renal diseases that involve the preceding three components -The center also provides a framework for training fellows in gastroenterology and hepatology to become independent investigators. The center is funded primarily through individual investigator-initiated extramural research grant support from the National Institutes of Health (NIH) as well as multi-investigator grants including RO1, PO1, UO1 and R24.