Spatial Proteome Reorganization of a Photosynthetic Model Cyanobacterium in Response to Abiotic Stresses

Spatial proteome reorganization in response to a changing
environment
represents a different layer of adaptation mechanism in addition to
differential expression of a subset of stress responsive genes in
photosynthetic organisms. Profiling such reorganization events is
critically important to extend our understanding how photosynthetic
organisms adapt to adverse environments. Thus, we treated a unicellular
photosynthetic model cyanobacterium, Synechocystis sp. PCC 6803 (hereafter referred to as Synechocystis), with five different types of abiotic stresses including nitrogen
starvation, iron deficiency, cold, heat, and darkness, and systematically
identified proteins showing stress-induced differential expression
and/or redistribution between the membrane and the soluble fractions
using a quantitative proteomics approach. A number of proteins showing
such a redistribution in response to a single or multiple types of
abiotic stresses were identified. These include 12 ribosomal proteins
displaying unanimous cold-induced redistribution to the membrane and
the protein FurA, a master regulator of iron acquisition, displaying
iron deficiency- and nitrogen starvation-induced redistribution to
the membrane. Such findings shed light on a novel regulatory mechanism
underlying the corresponding stress responses, and establish the results
in the present study as an important resource for future studies intended
to understand how photosynthetic organisms cope with adverse environments.