Rapid spatiotemporal patterning of cytosolic Ca2+ underlies flagellar excision in Chlamydomonas reinhardtii

Plant J. 2008 Feb;53(3):401-13. doi: 10.1111/j.1365-313X.2007.03349.x. Epub 2007 Dec 12.


Ca(2+)-dependent signalling processes are implicated in many aspects of flagella function in the green alga, Chlamydomonas. In this study, we examine the spatiotemporal dynamics of cytosolic Ca2+ ([Ca2+](cyt)) in single Chlamydomonas cells during the process of flagellar excision, using biolistically loaded calcium-responsive dyes. Acid-induced deflagellation occurred in parallel with a single transient elevation in whole-cell [Ca2+](cyt), which was absent in the acid deflagellation-deficient adf1 mutant. Deflagellation could also be induced by elevated external Ca2+ ([Ca2+](ext)), which promoted very rapid spiking of [Ca2+](cyt) across the whole cell and in the flagella. We also detected very rapid apically localised Ca2+ signalling events with an approximate duration of 500 msec. Ninety-seven per cent of deflagellation events coincided with a rapid elevation in [Ca2+](cyt) in the apical region of the cell, either in the form of a whole cell or an apically localised increase, indicating that [Ca2+](cyt) elevations in the apical region play an underlying role in deflagellation. Our data indicate that elevated [Ca2+](ext) acts to disrupt Ca2+ homeostasis which induces deflagellation by both Adf1-dependent and Adf1-independent mechanisms. Elevated [Ca2+](ext) also results in further [Ca2+](cyt) elevations after the main period of whole cell spiking which are very strongly associated with deflagellation, exhibit a high degree of apical localisation and are largely absent in the adf1 mutant. We propose that these later elevations may act as specific signals for deflagellation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium / physiology
  • Chlamydomonas reinhardtii / cytology
  • Chlamydomonas reinhardtii / metabolism*
  • Cytosol / metabolism*
  • Flagella / metabolism*
  • Microscopy, Confocal
  • Signal Transduction / physiology


  • Calcium