Annexins: Components of the Calcium and Reactive Oxygen Signaling Network

Arabidopsis Annexin1 Mediates the Radical-Activated Plasma Membrane Ca2+- and K+-Permeable Conductance in Root Cells

“…Overdeveloping the silver-stained gel (40 min) revealed very-low-level contaminants that were mostly also present in the buffer (Figure 6). To exclude the possibility that these contaminants were contributing to transport activity in PLB, the highly purified ANN1 preparation was immunoprecipitated for use in control experiments (Laohavisit et al, 2009(Laohavisit et al, , 2010.…”

“…In elongation, the conductance lies downstream of the Respiratory Burst Oxidase Homolog C (RBOHC) NADPH oxidase (Foreman et al, 2003) that is the initial source of ROS. The conductance resembles that formed by purified maize (Zea mays) annexins incorporated into artificial bilayers containing a lipid peroxidation product (Laohavisit et al, 2010). Hence, an Arabidopsis annexin could be responsible for forming the PM OH _ -activated Ca 2+ conductance.…”

“…Annexins are abundant throughout the plant kingdom (reviewed in Laohavisit and Davies, 2011a), and some contain the charged residues found in the hydrophobic pore of channel-forming animal annexins (Kourie and Wood, 2000;Laohavisit et al, 2009;Laohavisit and Davies, 2011a). Of these, Capsicum annuum annexin32/24 (ANN32/24) mediates Ca 2+ influx in liposomes (Hofmann et al, 2000), while maize annexins ANN33 and ANN35 support a Ca 2+ -permeable conductance in planar lipid bilayers (PLBs) (Laohavisit et al, 2009(Laohavisit et al, , 2010, and Arabidopsis ANN1 forms a K + -permeable channel in PLB (Gorecka et al, 2007). More compelling evidence for annexins as ion transport pathways requires electrophysiological analysis of annexin mutants (Laohavisit et al, 2009;Konopka-Postupolska et al, 2011).…”

“…annexins have been proposed to act as sensors of stress and stress-evoked ROS (Gorecka et al, 2007;Laohavisit et al, 2010;Laohavisit and Davies, 2011a). In roots of Arabidopsis under salt stress, preventing the formation of or scavenging OH _ compromises the stability of the newly made mRNAs encoding for the PM Na + /H + exporter Salt Overly Sensitive1 (SOS1; Chung et al, 2008).…”

The Rice Monovalent Cation Transporter OsHKT2;4: Revisited Ionic Selectivity

“…These results were exciting for the plant ion transport community, since in addition to the fact that they raised questions of structural evolution within the HKT family, at least for the former of these studies, they identified OsHKT2;4 as a potential actor of plant cell Ca 2+ signaling, in which very few proteins playing a role as Ca 2+ transporters or channels have been clearly identified at the molecular level so far (White et al, 2002;Ali et al, 2007;Cho et al, 2009;Laohavisit et al, 2010Laohavisit et al, , 2012.…”