Carole Liedtke, BA, PhD, MBA

Contact Information

10900 Euclid Ave, BRB 824
Cleveland, OH 44106
Phone: 216-368-4629
Fax: 216-368-1693
carole.liedtke@case.edu

Links

Carole Liedtke, BA, PhD, MBA

Professor Emeritus

  • Division: Pulmonology, Allergy and Immunology

Bio

In 1966, Carole Liedtke received her B.A. in Chemistry from Miami University. Dr. Liedtke was awarded her Ph.D. in 1980 from Case Western Reserve. She worked as a Post-doctoral fellow in Pediatrics and Pharmacology before becoming an Instructor, Assistant Professor in 1986, an Associate Professor in 1991 and a full Professor in 2000.

Research Interests

The vectorial movement of electrolytes Na and Cl across epithelia is a highly regulated physiological process that is vital for maintaining electrolyte and volume homeostasis. In epithelia lining the renal tubules and airway segments, two plasma membrane ion transporters play critical roles. One, a basolateral Na-K-Cl cotransport (NKCC1) is rate limiting for overall epithelial Cl and fluid secretion. Second, an apical Cl channel (CFTR, cystic fibrosis transmembrane conductance regulator) mediates energy-efficient movement of Cl from the cell into the lumen. NKCC1 and CFTR are regulated by distinct adrenergic receptors, protein kinases and phosphatases and protein binding partners. We identify and characterize proteins, lipids, and second messengers in signaling pathways from membrane receptor to transport proteins in order to discern how epithelial cells transmit signals with high fidelity. Distinct protein-protein interactions necessary for activation of a specific Cl transport protein are characterized by the dynamics and kinetics of the interaction and protein modifications which modulate the interaction.

In airway epithelia, NKCC1 supplies Cl for secretion; hence, manipulation of NKCC1 activity by infectious agents, mediators or drugs compromises baseline Cl secretion and response to hyperosmotic stress. I am dissecting signal transduction cascades involved in activation of NKCC1. Our current studies focus on protein-protein interactions of protein kinases and phosphatases with the amino terminus of NKCC1. More recently, we discovered binding of a small molecular weight cytosolic protein to the carboxyl terminus of NKCC1, which apparently regulates ubiquitination and thus membrane expression of NKCC1. We are now investigating how the protein complexes regulate NKCC1 activation and membrane expression using techniques from protein biochemistry, mass spectrometry, cell physiology, bioinformatics and molecular biology. One goal of this project is to determine how to NKCC1 activity can be manipulated to normalize Cl secretion.

Several multi-domain adaptor proteins have been identified as key regulators of CFTR membrane localization and activity. These adaptors integrate crucial functions including a) tethering of CFTR to the actin cytoskeleton and suppression of CFTR endocytosis; b) CFTR clustering with other membrane proteins, including receptors and channels/transporters; c) integrating signaling and acting as scaffolds for other CFTR regulatory proteins, including kinases. We have identified two adaptors, NHERF1 and filamin A (FlnA), and a scaffold RACK1 as necessary for maintenance of physiological CFTR levels at the membrane and for activation of CFTR, respectively. The long-term goal of this project is to determine how CFTR-interacting proteins regulate the membrane localization and channel properties of CFTR. In addition, we want to determine how these CFTR-regulatory processes can be modulated to ameliorate pathologies caused by dysregulation of epithelial ion transport and hydration.