A Regulatory Role for 14-3-3 Proteins in the Starch Biosynthetic Pathway of Zea mays

Starch derived from cereal endosperm is responsible for supporting humanity’s global caloric requirements and is applied in various industrial applications. Semi-crystalline starch granules are comprised of glucose polymers, amylose and amylopectin, which are synthesized by four classes of enzymes including ADP-glucose pyrophosphorylase (AGPase), starch synthases (SS), starch branching enzymes (SBE), and starch debranching enzymes (DBE). Several SS and SBE isoforms form large phosphorylation-dependent heteromeric protein complexes. A class of eukaryotic proteins called “14-3-3” dimerize and interact with phosphorylated clients to regulate enzymatic activity, localization and protein interactions. A series of bioinformatic and biochemical techniques identified GF14-6 as the only detectable 14-3-3 isoform in maize amyloplasts. Recombinant GF14-6 was shown to interact with SSI, SBEIIa and SBEIIb in affinity bait assays. Reciprocal interactions using recombinant SBEIIb demonstrated phosphorylation-dependent interactions with endogenous 14-3-3s. These results point towards a regulatory role for 14-3-3 proteins regulating starch biosynthesis in maize endosperm.

Grantor dc:publisher

University of Guelph

Author dc:creator

• Carswell, Matthew

Advisor dc:contributor.advisor

• Emes, Michael

• Starch
• 14-3-3
• protein-protein interactions
• phosphorylation

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10214/23753

OAI record oai:identifier

https://atrium.lib.uoguelph.ca/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Aatrium.lib.uoguelph.ca%3A10214%2F23753