FOR 5046:  Integrated analysis of epithelial SLC26 anion transporters - from molecular structure to pathophysiology

• Subject Area: Medicine
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426950122

The Solute Carrier family 26 (SLC26) includes functionally versatile anion transporters present throughout all kingdoms of life. The human genome encodes ten functional homologs, several of which are causally associated with severe human diseases, such as chloride losing diarrhea, hypothyroidism, male infertility, skeletal malformation, brain edema, or deafness. Association with human diseases substantiate the high physiological and pathophysiological importance of SLC26 transporters, yet fundamental principles of their function, regulation, and role in cell and organ physiology remain poorly understood. Progress has been slowed by missing structural information at the molecular level and lack of suitable model systems at the physiological level. The recent determination of the structural architecture of SLC26 proteins and technical developments towards improved model systems represent major breakthroughs that will now allow us to analyze selected SLC26 isoforms at unprecedented depth and level of detail. The integrative goal of this Research Unit is the analysis of structure, function, and regulation of selected SLC26 isoforms in both reduced molecular and complex physiological environments. We will focus particularly on the SLC26 isoforms A2, A3, A6, A9, and A11 with pathophysiological relevance in the kidney and intestine as prototypic epithelial transport organs. The Research Unit will (i) elucidate the structural basis of transport and its regulation by determining the atomic structures of SLC26 proteins, (ii) perform detailed structure-function analysis, (iii) bridge structural and functional data via molecular dynamics simulations for predicting transport mechanisms, (iv) determine how selected SLC26 transporters are regulated in cells by trafficking and by protein-protein interactions, and (v) dissect the function of these specific SLC26 homologs in solute transport in gastrointestinal and renal epithelia. State-of-the-art technical approaches used in an interdisciplinary manner will be key to achieve these aims. These include single-particle cryo-EM, all-atom molecular dynamics simulations, electrophysiology, and fluorescence spectroscopy at the molecular level. Cellular biology will be addressed by interaction proteomics combined with live-cell fluorescence microscopy. For elucidating physiology and pathophysiology at the systemic level, we will study human organoids as a near-native in-vitro approach as well as new conditional mouse models. A platform for generation of nanobodies directed against all targeted SLC26 isoforms will provide pivotal tools for structure determination, proteomics and imaging. We expect that the results of this research program will reveal novel molecular mechanisms, cellular pathways, and organ functions, which will be accessible to molecular interventions and together may provide a foundation for future translational research.

• DFG Programme: Research Units

Projects

• Coordination Funds (Applicant Oliver, Dominik )
• Deciphering the transport metabolomes of SLC26A3, SLC26A6 and SLC26A9 in the human gastrointestinal tract (Applicant Seidler, Ursula )
• Functional specialization of transporting and non-transporting SLC26 proteins (Applicants Machtens, Jan-Philipp ;  Oliver, Dominik )
• Molecular composition and structure of the SLC26A5 microenvironment in sensory outer hair cells (Applicant Oliver, Dominik )
• P1 – Disorder-function relationships in SLC26 transporters (Applicant Geertsma, Eric )
• Physiological function and transport mode of the anion transporter SLC26A9 in the gastric and alveolar epithelium (Applicant Seidler, Ursula )
• Physiological significance of the interaction between SLC26A3 and SLC26A6 with CFTR or NHE3 for secretion and absorption in the intestine (Applicants Amiri, Mahdi ;  Lamprecht, Hans Georg )
• PZ – Nanobodies for multilevel examination of SLC26 transporters (Applicant Geertsma, Eric )
• The role of SLC26A2 in enteric and renal oxalate transport (Applicants Knauf, Felix ;  Scholl, Ute )
• Transport mechanisms and cellular functions of SLC26A11 (Applicants Alfonso-Prieto, Ph.D., Mercedes ;  Fahlke, Christoph )

• Spokesperson: Professor Dr. Dominik Oliver