What is LOV? An Analysis of LOV Domains and Their Potential Role in Plant Oxygen Sensing

Abstract

In order to survive, grow and reproduce, it is crucial for organisms to sense and react to their environments. Light-Oxygen-Voltage (LOV) domains are well-known environmental sensors that are widespread in bacteria, archaea, plants and other eukaryotes. While plant LOV proteins have yet only been found to have light-sensing roles, the conservation and divergent roles of LOV domains in other kingdoms of the tree of life suggests a possible additional role for plant LOV domains in oxygen sensing. Here, we describe the role of plant LOV domains in light perception and we investigate whether plant LOV proteins could indeed function in oxygen sensing by analyzing the roles and mechanisms of LOV domains in light sensing proteins of Arabidopsis thaliana as well as oxygen sensing roles of LOVs in other species. Both commonalities and differences are seen for light-sensing proteins regarding the roles of their LOV domains, and their functioning appears to be flexible. Looking at the oxygen sensor proteins, it is noticeable that all described oxygen-sensing proteins function via changes in redox status of the FMN/FAD cofactors, and that it was often seen to go together with light sensing functions. Known plant LOV proteins could thus possibly have an extended redox-based oxygen sensing role. Lastly, as some highly similar PAS domains are found to be involved in Light-Oxygen-Voltage, we propose a new protein family LOV related (LOVr).