Trans-plasma membrane electron transfer is achieved by b-type cytochromes of different families, and plays a fundamental role in diverse cellular processes involving two interacting redox couples that are physically separated by a phospholipid bilayer, such as iron uptake and redox signaling. Despite their importance, no direct recordings of trans-plasma membrane electron currents have been described in plants. In this work, we provide robust electrophysiological evidence of trans-plasma membrane electron flow mediated by a soybean (Glycine max) cytochrome b561 associated with a dopamine b-monooxygenase redox domain (CYBDOM), which localizes to the plasma membrane in transgenic Arabidopsis (Arabidopsis thaliana) plants and CYBDOM complementary RNA-injected Xenopus laevis oocytes. In oocytes, two-electrode voltage clamp experiments showed that CYBDOM-mediated currents were activated by extracellular electron acceptors in a concentration-and type-specific manner. Current amplitudes were voltage dependent, strongly potentiated in oocytes preinjected with ascorbate (the canonical electron donor for cytochrome b561), and abolished by mutating a highly conserved His residue (H292L) predicted to coordinate the cytoplasmic heme b group. We believe that this unique approach opens new perspectives in plant transmembrane electron transport and beyond.
|Titolo:||Direct Recording of Trans-Plasma Membrane Electron Currents Mediated by a Member of the Cytochrome b561 Family of Soybean|
|Settore Scientifico Disciplinare:||Settore BIO/04 - Fisiologia Vegetale|
|Data di pubblicazione:||ott-2015|
|Data ahead of print / Data di stampa:||1-ott-2015|
|Digital Object Identifier (DOI):||10.1104/pp.15.00642|
|Appare nelle tipologie:||01 - Articolo su periodico|