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 transporterspresent throughout all kingdoms of life. The human genome encodes ten functionalhomologs, several of which are causally associated with severe human diseases, such aschloride losing diarrhea, nephrolithiasis, hypothyroidism, male infertility, skeletalmalformation, brain edema, or deafness. Association with human diseases and organspecificexpression profiles substantiate the high physiological and pathophysiologicalimportance of SLC26 proteins, yet fundamental principles of their function, regulation, androle in cell and organ physiology remain unaddressed or poorly understood. Progress hasbeen slowed by missing structural information at the molecular level and lack of suitablemodel systems at the physiological level. The recent determination of the structuralarchitecture of SLC26 proteins and technical developments towards improved modelsystems represent major breakthroughs that will now allow us to analyze selected SLC26isoforms at unprecedented depth and level of detail.The integrative goal of this Research Unit is the analysis of structure, function, and regulationof selected SLC26 isoforms in both reduced molecular and complex physiologicalenvironments. We will focus particularly on the SLC26 isoforms A2, A3, A6, A9, and A11 thatare presumed to have high relevance in the kidney and intestine as prototypic epithelialtransport organs and are associated with pathophysiology. The Research Unit will (i)elucidate the structural basis of transport, substrate recognition, and regulation bydetermining the atomic structures of SLC26 proteins, (ii) perform detailed functionalcharacterization in terms of structure-function relationships, (iii) bridge structural andfunctional data via molecular dynamics simulations for predicting transport mechanisms, (iv)determine how selected SLC26 transporters are regulated in cells by trafficking and byprotein-protein interactions, and (v) dissect the function of these specific SLC26 homologs insolute transport in gastrointestinal and renal epithelia.State-of-the-art technical approaches used in an interdisciplinary manner will be key toachieve these aims. These include single-particle cryo-EM, all-atom molecular dynamicssimulations, electrophysiology, and fluorescence spectroscopy at the molecular level.Cellular biology will be addressed by interaction proteomics and complexome profilingcombined with live-cell fluorescence microscopy. For elucidating physiology andpathophysiology at the systemic level, we will use and refine human organoids as a nearnativein-vitro approach as well as new conditional mouse models. A platform for generationof nanobodies directed against all targeted SLC26 isoforms will provide pivotal tools forstructure 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 interventionsand 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 )
• Molecular dynamics of SLC26 transporters (Applicant Machtens, Jan-Philipp )
• Molecular mechanism and cellular function of channel-like SLC26 proteins (Applicants Fahlke, Christoph ;  Oliver, Dominik )
• P1 – Comprehensive structural description of SLC26 membrane transport and its modulation (Applicant Geertsma, Eric )
• PZ – Nanobodies for multilevel examination of SLC26 transporters (Applicant Geertsma, Eric )
• Regulation of SLC26 proteins by plasma membrane recycling and novel interacting proteins (Applicants Lamprecht, Hans Georg ;  Wittig, Ilka )
• SLC26A2 function in the kidney (Applicant Scholl, Ute )
• Understanding the transport mechanisms of the electrogenic transporters SLC26A3 and SLC26A6 (Applicant Oliver, Dominik )

• Spokesperson: Professor Dr. Dominik Oliver