Search tips
Search criteria

Results 1-2 (2)

Clipboard (0)

Select a Filter Below

Year of Publication
1.  Multiple receptor complexes assembled for transmitting CLV3 signaling in Arabidopsis 
Plant Signaling & Behavior  2010;5(3):300-302.
In Arabidopsis, the feedback regulatory loop between CLAVATA3 (CLV3) signaling pathway and transcription factor, WUSCHEL (WUS) plays a significant role in shoot apical meristems (SAM) maintenance. Previously, CLV1/CLV2 heterodimers were supposed to perceive and transmit CLV3 signaling. Recent genetic analysis isolated a novel receptor kinase, CORYNE (CRN), which was found to be involved in the CLV3 pathway. Therefore, new hypothesis was put forward that CRN probably acts with CLV2 to transmit CLV3 in parallel with CLV1 based on genetic analysis. In our recent work, we took advantage of firefly luciferase complementation imaging (LCI) assay to analyze the interactions among CLV1, CLV2 and CRN in both Arabidopsis thaliana protoplasts and Nicotiana benthamiana leaves. We identified the physical interaction between CLV2 and CRN in the absence of CLV3 and found some interesting phenomenon such as CLV1, CLV2 and CRN may form a complex, and that CRN was able to form homodimers. These new observations make the relationships among these three proteins more complex than that indicated in two-parallel pathway model. Combining current genetic and our new biochemical evidence, a more possible and detailed model for CLV3 pathway was developed.
PMCID: PMC2881284  PMID: 20220313
CLAVATA3 (CLV3) signaling pathway; firefly luciferase complementation imaging (LCI) assay; Arabidopsis thaliana protoplasts; Nicotiana benthamiana leaves; homodimers
2.  Disruption of actin filaments induces mitochondrial Ca2+ release to the cytoplasm and [Ca2+]c changes in Arabidopsis root hairs 
BMC Plant Biology  2010;10:53.
Mitochondria are dynamic organelles that move along actin filaments, and serve as calcium stores in plant cells. The positioning and dynamics of mitochondria depend on membrane-cytoskeleton interactions, but it is not clear whether microfilament cytoskeleton has a direct effect on mitochondrial function and Ca2+ storage. Therefore, we designed a series of experiments to clarify the effects of actin filaments on mitochondrial Ca2+ storage, cytoplasmic Ca2+ concentration ([Ca2+]c), and the interaction between mitochondrial Ca2+ and cytoplasmic Ca2+ in Arabidopsis root hairs.
In this study, we found that treatments with latrunculin B (Lat-B) and jasplakinolide (Jas), which depolymerize and polymerize actin filaments respectively, decreased membrane potential and Ca2+ stores in the mitochondria of Arabidopsis root hairs. Simultaneously, these treatments induced an instantaneous increase of cytoplasmic Ca2+, followed by a continuous decrease. All of these effects were inhibited by pretreatment with cyclosporin A (Cs A), a representative blocker of the mitochondrial permeability transition pore (mPTP). Moreover, we found there was a Ca2+ concentration gradient in mitochondria from the tip to the base of the root hair, and this gradient could be disrupted by actin-acting drugs.
Based on these results, we concluded that the disruption of actin filaments caused by Lat-B or Jas promoted irreversible opening of the mPTP, resulting in mitochondrial Ca2+ release into the cytoplasm, and consequent changes in [Ca2+]c. We suggest that normal polymerization and depolymerization of actin filaments are essential for mitochondrial Ca2+ storage in root hairs.
PMCID: PMC2923527  PMID: 20334630

Results 1-2 (2)