Cephalopod Biochemistry

Our group studies the chemical and physical origins of biological color in dynamic systems like cephalopods, including squid, octopus, and cuttlefish. Our primary focus is on the role of dermal chromatophore organs as active components of color change and their function in facilitating camouflage, where we study the pigmented nanostructures localized within chromatophores and more recently the musculoskeletal system surrounding these nanostructures that supports motility and signaling. 

Beginning with the first mass spectrometric analysis of squid chromatophore tissue, we identified the abundance of phenoxazone-based chromophores (xanthommatin, Xa, and its decarboxylated form, DC-Xa) that combine to contribute to a broad-range of color spanning the UV-visible spectra. Our lab worked with a team of researchers across 4 institutions to compile the first annotated chromatophore proteome, which was used to describe the biochemical origins of both pigmentary and newly discovered structural color emanating in precise register in squid chromatophores. This exciting finding highlighted an extremely rare case of how pigments and protein-based nanostructures are tightly co-localized within a single, organ to give rise to rapid (~100 msec) changes in color. We expanded this finding with computational analyses supported by mass spectrometry to show that the Xa pigments are confined to nanostructured granules composed of lens crystallin proteins in the chromatophore that we describe as having dual roles: stabilizing the charge environment of the absorptive pigment molecules and simultaneously enabling optical scattering that could aid in color amplification during actuation. These findings suggest a functional convergence between the eyes and skin of the animals that is the subject of ongoing studies.