| Starch is an important polymer of glucose molecules synthesized within plastids by four classes of enzymes including ADP-glucose pyrophosphorylase (AGPase), starch synthases (SS), branching enzymes (BE), and debranching enzymes (DBE). Multi-enzyme complexes appear to regulate starch synthesis in cereal endosperms in a phosphorylation-dependent manner and may interact with 14-3-3 proteins. 14-3-3 proteins are a eukaryotic class of proteins involved in various cellular roles and further, are also located in plastids. 14-3-3s can form dimers and interact with multiple phosphoproteins simultaneously. This research investigated the role of 14-3-3 proteins in starch synthesis in wheat endosperm through biochemical studies. Using affinity chromatography, recombinant wheat endosperm 14-3-3 protein was found to interact with SSI, SSII, BEIIa, and BEIIb. Zymogram analysis demonstrated changes in activities of SSIII, BEII(a+b), isoamylase, and amylase-like enzymes following incubation with 14-3-3 protein. The work presented suggests a regulatory role for 14-3-3 proteins in storage starch biosynthesis. |
