Membranes as hubs of biogenic crystallization (HFSPO-Research Grant)

 

Many organisms, from microalgae to vertebrates, build molecular crystals inside their cells to serve essential functions, from vision to nitrogen storage. Zebrafish are a striking example: specialized pigment cells called iridophores produce guanine crystals inside membrane-bound organelles, the iridosomes, and these crystals act as remarkably efficient light reflectors. What makes them extraordinary is their shape. Biogenic guanine crystals grow flat and thin, a geometry that requires thermodynamically unfavourable molecular interactions and that we still cannot reproduce synthetically under physiological conditions.

MetaCrystal asks how cells achieve this, by focusing on a structure that has so far been overlooked: the lipid membrane that surrounds each crystal. We propose that this membrane acts both as a platform, concentrating purines and organising the lipids, proteins and transporters that nucleate the crystal, and as a constraint, limiting axial growth through its own biophysical properties and its contacts with other organelles. To test this, we combine organellar multiomics of purified zebrafish iridosomes, quantitative measurements and optical manipulation of membrane properties in iridophore cultures, molecular dynamics simulations of iridosomal bilayers, and bottom-up reconstitution of purine crystallization inside model membranes. Our aim is to build a metabolically active synthetic iridosome and define the minimal membrane conditions required to grow a functional, anisotropically shaped crystal.

Beyond its fundamental interest, understanding how cells control crystallization matters for pathological crystallization in humans, such as gout and kidney stones, and for the design of bioinspired optical materials.

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Team Collaborators:​

• Rita Mateus — Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) and Cluster of Excellence Physics of Life, TU Dresden, Germany. 

• Viviana Monje-Galvan — Department of Chemical and Biological Engineering, University at Buffalo (SUNY), USA. 

 

 

 

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