A cyanobacterial b-actin-like protein, responsible for lichenized Nostoc sp. motility towards a fungal lectin

Abstract

Lichenized Nostoc cells isolated from the lichen Peltigera canina develop chemotactic movement towards a lectin purified from the lichen thallus. Inhibitors of cytoskeleton dynamics, such as phalloidin, latrunculin A and blebbistatin, impede cell displacement. The inhibition of chemotaxis produced by the combined action of phalloidin and blebbistatin is largely reversed by GTP and its analogs, GTP(c)S and GDP(b)S, as well as by cyclic AMP. Movement implies a rearrangement of the cytoskeleton causing cell polarity, which is, in turn, inhibited by phalloidin and latrunculin A, as revealed by confocal microscopy. F-actin fibers composing Nostoc cytoskeleton have been visualized by immunocytochemical techniques associated with transmission electron microscopy.