Figure 6

Regulatory hypotheses for how Rubisco becomes selectively localized to the central compartment chloroplasts (CCC) of Bienertia chlorenchyma cells. Regulatory point one, (yellow boxes) is the selective targeting or import of rbcL mRNA binding proteins (RBP) such as RLSB, or other proteins necessary for Rubisco assembly. Regulatory point two, is the translation of rbcL, where in the CCC under reduced conditions (GSH, green box) rbcL RBPs would increase translation of rbcL, while in the peripheral compartment chloroplasts (PCC) under elevated oxidized glutathione conditions (GSSG, red box), rbcL RBPs would not bind to rbcL, due to incorrectly folded rbcL binding to rbcL slowing translation. Regulatory point three, is the interaction of rbcL with stromal chaperonins and assembly of Rubisco, which in the PCC could be impeded due to a lack of chaperonins like RAF1 or the redox state of the chloroplast. Regulatory point four, is the stability or degradation of Rubisco which might be increased in the PCC due to elevated H₂O₂ concentrations. Figure adapted from [23, 27, 66].