NANOFILAMENT DEPENDENT MOTILITY IN DINOFLAGELLATES

In dinoflagellates, as in many eukaryotes, several kinds of nanofilame nts have been described: some are organized in bundies showing a stric t periodicity, some are not; most are contractile upon a rise in Ca2concentration, some are not. In any case, their contractile properties appear to be ATP independent. They are present in all cell types stud ied so far, and are typically found in association with the centrioles -basal bodies where they are suggested to play a role in MTOC structur e, position and function. Nanofilaments are all about 2-4 nm in diamet er, interact with microtubules, and are insoluble filaments, though to a variable extent. We propose that the nanofilaments may play a struc tural and/or active role complementary to intermediate filaments.