Structural basis for the recruitment of glycogen synthase by glycogenin

• DOI: 10.1073/pnas.1402926111
• Publication Date: 2014-07-01T14:07:52Z
• Authors: Elton Zeqiraj; Xiaojing Tang; Roger W. Hunter; Mar García-Rocha; Andrew Judd; Maria Deak; Alexander von Wil...; Igor Kurinov; Joan J. Guinovart; Mike Tyers; Kei Sakamoto; Frank Sicheri
• Keywords: Mice, Knockout; 0301 basic medicine; Glucose metabolism; glycogenesis; 570; Glycosylation; Cell-Free System; Starch; Energy metabolism; Crystallography, X-Ray; Mice; Structure-Activity Relationship; 03 medical and health sciences; Glycogen Synthase; Glucosyltransferases; Animals; Protein Multimerization; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Protein Structure, Quaternary; Cells, Cultured; Glycogen; Glycoproteins; Protein Binding

Significance The body stores excess blood glucose as glycogen, a sugary substance that contains up to 55,000 glucose molecules joined together as a chain, mostly in liver and muscle cells. Conversion of glucose to glycogen and glycogen to glucose in these cells plays an important role in regulating blood glucose levels. Glycogen ensures that we don’t run out of fuel during prolonged exercise. To make glycogen from blood sugar, cells need two enzymes: glycogenin and glycogen synthase. Glycogenin kick starts the process by first linking to itself a string of glucose residues and then recruiting glycogen synthase to elaborate this “seed” glycogen particle. Here, we describe the molecular details of how these two enzymes come together and begin to make glycogen.