Membrane-mineral interaction in diatom silica morphogenesis
The biological formation of silica is a widely occurring phenomenon. The complex nano- and micropatterned silica architectures produced by diatoms and other silica-forming organisms display unique materials properties, yet are inaccessible to materials synthesis today. They are formed in membrane-bound, intracellular compartments termed silica deposition vesicles (SDVs). How SDVs function as cellular machines for silica morphogenesis is not well understood. Recent discoveries hint at the importance of membrane-mineral interactions: i) several SDV membrane proteins were discovered in the model diatom Cyclotella nana (formerly Thalassiosira pseudonana) and shown to be involved in the formation characteristic of biosilica features like ribs93,94, pores74,93–95 and tubes74; ii) cryogenic electron tomography (cryoET) revealed curved membrane invaginations that co-localize with nascent nano-pores in the silica underneath96, suggesting that the SDV membrane contains subdomains with different silica morphogenesis properties (Figure P3).
The aim of this project is to test the hypothesis that the SDV membrane and the developing silica inside the SDV form a coupled morphogenesis system, wherein spatio-temporal patterns of membrane properties (lipid/protein composition, membrane curvature, silica affinity) guide the morphogenesis of biosilica.