Ca2+ elevations disrupt interactions between intraflagellar transport and the flagella membrane in <i>Chlamydomonas</i>

ABSTRACT The movement of ciliary membrane proteins is directed by transient interactions with intraflagellar transport (IFT) trains. green alga Chlamydomonas has adapted this process for gliding motility, using retrograde IFT motors to move adhesive glycoproteins in the flagella membrane. Ca2+ signalling contributes directly process, although uncertainty remains over mechanism through which it acts. Here, we show that elevations initiate paused trains, accumulate at distal end adherent flagella, but do not influence other processes. On highly surfaces, exhibit high-frequency prevent accumulation Flagella disrupt IFT-dependent microspheres along membrane, suggesting acts disrupting an interaction between trains and glycoproteins. By regulating extent on surface interact motor axoneme, allows precise control traction force motility flagella.