The experiment essentially investigates the association between endoplasmic reticulum and mitochondria.
Introduction
Mitochondrion is a cell organelle, which moves along actin filaments. They are also calcium storage sites in the cell. The positioning and movement is influenced by membrane-cytoskeleton interactions. Reports suggest that the release of calcium from mitochondria and endoplasmic reticulum is influenced by structural changes in microtubules.
Materials used.
1. YFP-HDEL/atp-mito-CFP line.
2. 2μM Latrunculin-B
3. Ethanol control.
4. Arabidopsis Sail359/Aequroin line expressing atp-GFP-Aequorin.
Procedure
Actin depolymerization affects mitochondrial clustering and movements. In the experiment, YFP-HDEL/ atp-mito-CFP line was treated with 2μM lat-B for 3 hours and 24 hours. Figure 1 shows the effects, in percentage, on mitochondrial clustering and movements.
Results
Effects of Latrunculin- B on mitochondrial morphology and motility on wild type Arabidopsis
Stable transgenic Arabidopsis Sail359/Aequroin line expressing atp-GFP:Aequorin was treated with (2μM) Lat-B for 3 hours and 24 hours. From the results on figure 1, it is clear that mitochondria are clustered in Lat-B but, there is no effect at all in the ethanol control.
Figure 1: The effects of actin depolymerization on mitochondrial clustering and movements in YFP-HDEL/atp-CFP line, when treated with 2μM Lat-B and ethanol control for 3 hours and 24 hours.
The figures are the means of three independent experiments; error bars represent the standard errors of the means.
Discussion
Lat-B depolymerized actin filaments causing the release of calcium from mitochondria in the Arabidopsis root hairs. Cytoplasmic calcium concentration increases. Treatment with lat-B also disrupted mitochondrial movement along actin filaments increasing the clustering of mitochondria.
Conclusion
Gestel, K. V., Kohler, R. H., & Verbelen, J. P. (2006, AUGUST 27). Plant mitochondria move on F‐actin, but their positioning in the cortical cytoplasm depends on both F‐actin and microtubules. Retrieved OCTOBER 02, 2012, from JOURNAL OF EXPERIMENTAL BOTANY: http://jxb.oxfordjournals.org/content/53/369/659.full
Wang, Y., Zhu, Y., Ling, Y., Zhang, H., & Liu, P. (2010, MARCH 24). Disruption of actin filaments induces mitochondrial Ca2+ release to the cytoplasm and [Ca2+]c changes in Arabidopsis root hairs. Retrieved OCTOBER 02, 2012, from BIO MED CENTRAL: http://www.biomedcentral.com/1471-2229/10/53
Zheng, M., Beck, M., Muller, J., & Chen, T. (2009, JUNE 18). Actin Turnover Is Required for Myosin-Dependent Mitochondrial Movements in Arabidopsis Root Hairs. Retrieved OCTOBER 02, 2012, from PLOSONE: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005961
