Abstract
Mimosa pudica L. rapidly closes its leaves and bends its petioles downward when mechanically stimulated. It has been suggested that the actin cytoskeleton is involved in the bending motion since both cytochalasin B and phalloidin inhibit the motion. In order to clarify the mechanism by which the actin cytoskeleton functions in the motion, we attempted to find actin-modulating proteins in the M. pudica plant by DNase I-affinity column chromatography. The EGTA-eluate from the DNase I column contained proteins with apparent molecular masses of 90- and 42-kDa. The 42-kDa band consisted of two closely migrating components: the slower migrating component was actin while the faster migrating components was a distinct protein. The eluate showed an activity to sever actin filaments and to enhance the rate of polymerization of actin, both in a Ca2+-dependent manner. Microsequencing of the faster migrating 42-kDa protein revealed its similarity to proteins in the gelsolin/fragmin family. Our results provide the first biochemical evidence for the presence in a higher plant of a gelsolin/fragmin family actin-modulating protein that severs actin filament in a Ca2+-dependent manner.
Original language | English |
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Pages (from-to) | 243-249 |
Number of pages | 7 |
Journal | Journal of biochemistry |
Volume | 130 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2001 Aug |
Keywords
- Actin
- Actin-modulating protein
- F-actin severing protein
- Gelsolin/fragmin
- Mimosa pudica
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology