title: Extracellular Cysteine in Connexins: Role as Redox Sensors.
abstract: Connexin-based channels comprise hemichannels and gap junction channels. The opening of hemichannels allow for the flux of ions and molecules from the extracellular space into the cell and vice versa. Similarly, the opening of gap junction channels permits the diffusional exchange of ions and molecules between the cytoplasm and contacting cells. The controlled opening of hemichannels has been associated with several physiological cellular processes; thereby unregulated hemichannel activity may induce loss of cellular homeostasis and cell death. Hemichannel activity can be regulated through several mechanisms, such as phosphorylation, divalent cations and changes in membrane potential. Additionally, it was recently postulated that redox molecules could modify hemichannels properties in vitro. However, the molecular mechanism by which redox molecules interact with hemichannels is poorly understood. In this work, we discuss the current knowledge on connexin redox regulation and we propose the hypothesis that extracellular cysteines could be important for sensing changes in redox potential. Future studies on this topic will offer new insight into hemichannel function, thereby expanding the understanding of the contribution of hemichannels to disease progression.
authors: Facultad de Medicina, Centro de Fisiología Celular e Integrativa, Clínica Alemana Universidad del Desarrollo Santiago, Chile.
authors: Mauricio A
authors: MA
authors: Retamal
authors: Facultad de Ciencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso Valparaíso, Chile.
authors: Isaac E
authors: IE
authors: García
authors: Facultad de Ciencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso Valparaíso, Chile.
authors: Bernardo I
authors: BI
authors: Pinto
authors: Facultad de Ciencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso Valparaíso, Chile.
authors: Amaury
authors: A
authors: Pupo
authors: Facultad de Ciencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso Valparaíso, Chile.
authors: David
authors: D
authors: Báez
authors: Laboratorio de Neurobiología, Centro de Investigaciones Biomédicas, Universidad Andres Bello Santiago, Chile.
authors: Jimmy
authors: J
authors: Stehberg
authors: Laboratory of Cardiorespiratory Control, Center for Biomedical Research, Universidad Autónoma de ChileSantiago, Chile; Dirección de Investigación, Universidad Científica del SurLima, Perú
authors: Rodrigo
authors: R
authors: Del Rio
authors: Facultad de Ciencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso Valparaíso, Chile.
authors: Carlos
authors: C
authors: González
keywords: connexins; gap junction channels; gaseous transmitters; hemichannels; post-translational modification; redox potential