Comparative Ultrastructure and Physiology of Chromatophores, with Emphasis on Changes Associated with Intracellular Transport

Recent advances in our understanding of the mechanism of intracellulartransport in unicellular chromatophores are reviewed. Emphasisis placed on the possible role(s) of the three major cytoskeletalcomponents microtubules, intermediate filaments, and actin filaments.A comparative analysis of different chromatophore types suggeststhat these cytoskeletal fiber systems may play different roles,or at least seem to be involved to a varying degree, in intracellularpigment translocation. Ultrastructure, transport characteristics,and responses to pharmacological agents of a wide variety ofvertebrate and invertebrate chromatophores do show sufficientvariation to make one consider the possibility that the underlyingmechanisms also vary to some extent. It is hoped that the increaseduse of new methodological approaches, including microinjectionof single cells and the development of reactivatable cell models,will greatly aid us in our exploration of the physical-chemicalbasis of chromatophore motility.