Mastoparan alters subcellular distribution of profilin and remodels F-actin cytoskeleton in cells of maize root apices
2001
Baluška, F. | Witsch, M. von | Peters, M. | Hlavacka, A. | Volkmann, D.
Indirect immunofluorescence localization of profilin in cells of maize root apices revealed that this abundant protein was present both in the cytoplasm and within nuclei. Nucleo-cytoplasmic partitioning of profilin exhibits tissue-specific and developmental features. Mastoparan-mediated activation of heterotrimeric G-proteins, presumably through triggering a phosphoinositide-signaling pathway based on phosphatidylinositol-4,5-bisphosphate (PIP2), induced relocalization of profilin from nuclei into the cytoplasm of root apex cells. In contrast, PIP2 accumulated within nuclei of mastoparan-treated root cells. Intriguingly, cytoplasmic accumulation of profilin was associated with remodeling of F-actin arrays in root apex cells. Specifically, dense F-actin networks were dismantled and distinct actin patches became associated with the periphery of small vacuoles. On the other hand, disruption of F-actin with the G-actin sequestering agent latrunculin B does not affect the subcellular distribution of profilin or PIP2. These data suggest that nuclear profilin can mediate a stimulus-response action on the actin cytoskeleton which is somehow linked to a phosphoinositide-signaling cascade.
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