Reconstitution of Mineral Morphogenesis in Membrane-enclosed Compartments

• Applicants: Professor Dr. Stefan Diez; Professorin Dr. Claudia Steinem
• Subject Area: Biophysics ; Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 508949948

Biomineralization often takes place in membrane-enclosed compartments, where mineral precursors and accessory molecules are combined in a finite volume. Transfer of the mineral precursors to these membrane-enclosed compartments is realized by specialized vesicles that fuse with the compartment membrane. How the stepwise transfer of precursors and release into the confined membrane-enclosed compartment occurs as well as how the physico-chemical conditions and mineralization modifiers within the compartment influence mineral morphogenesis is not well under-stood. To get access to these parameters, we aim in this project at establishing a versatile in vitro system that allows us to (i) reconstitute membrane-enclosed compartments, (ii) add mineral-forming compounds in a stepwise manner via fusion of vesicles, and (iii) quantitatively investigate mineralization as function of the chemical and physical conditions of the membrane and inside the compartment. The novel motor-based vesicle transport in conjunction with a fusion system that we aim to establish is intended to allow for highly-localized fusion events and to mimic the natural vesicle-compartment fusion machineries believed to operate in biomineralization. In the project, we will focus on the mineral calcium carbonate. We will ask how the presence of different types of mineral precursors, organic mineralization modifiers, ions and molecular crowders inside the compartments alter the kinetics of mineralization as well as the final mineral. Furthermore, we aim at studying how sizes and shapes of the compartments as well as the composition of the enclosing lipid bilayers influence mineral morphology. Beyond contributing to our understanding of calcium carbonate mineral morphogenesis, we expect that our approach will provide the basis for studies on other minerals. The overall goal of our project will be the development of a fully synthetic system mimicking the natural multi-step process of biomineralization.

• DFG Programme: Research Grants