Premium
ON THE SIGNAL‐TRANSDUCTION CHAINS OF TWO Pfr‐ MEDIATED SHORT‐TERM PROCESSES: INCREASE OF ANCHORAGE and MOVEMENT OF Mougeotia CHLOROPLASTS
Author(s) -
Schonbohm Ekkehard,
Schönbohm Elfriede,
MeyerWegener Jens
Publication year - 1990
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1990.tb01775.x
Subject(s) - calmodulin , phytochrome , chloroplast , transduction (biophysics) , biophysics , signal transduction , vesicle , biology , botany , microbiology and biotechnology , actin , red light , chemistry , biochemistry , membrane , gene , enzyme
— We examined two published hypotheses on the signal‐transduction chain of the light‐oriented chloroplast movements in the fresh‐water alga Mougeotia. One hypothesis postulates a Ca 2 +‐influx controlled by a tetrapolar gradient of phytochrome in its far‐red light absorbing form (Pfr). The other hypothesis postulates anchorage sites for actin‐filaments even at those areas of the plasmalemma where phytochrome is in its inactive form (Pr). Calmodulin and Ca 2 +‐sequestering vesicles are assumed to be essential links of this transduction chain. To test these hypotheses we have studied the effects of Ca 2 +‐entry blockers, Ca 2 + deficiency and calmodulin antagonists on chloroplast movements and on chloroplast anchorage. None of our results support the Ca 2 +/calmodulin hypotheses mentioned above. The results and their implications (with regard to the role of Ca 2 ', calmodulin and anchorage sites) are discussed.