Glycogenin, the primer of glycogen synthesis, binds to actin

• Published in: FEBS letters Vol. 417; no. 3; pp. 355 - 359
• Main Authors: Baqué, Susanna, Guinovart, Joan J, Ferrer, Juan C
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 17.11.1997
• Subjects: Actin cytoskeleton; Actins - drug effects; Actins - metabolism; Amino Acid Sequence; Amino Acid Substitution; Animals; Binding Sites; Cell Line; Cell Nucleus - metabolism; Cloning, Molecular; COS Cells; Cytochalasin D - pharmacology; Cytosol - metabolism; GFP; Glucosyltransferases; Glycogen - biosynthesis; Glycogen metabolism; Glycogenin; Glycoproteins - biosynthesis; Glycoproteins - metabolism; Green fluorescent protein; Green Fluorescent Proteins; Liver - metabolism; Liver Glycogen - biosynthesis; Luminescent Proteins - biosynthesis; Muscle Proteins - biosynthesis; Muscle Proteins - metabolism; Muscle, Skeletal - metabolism; Mutagenesis, Site-Directed; Peptide Fragments - chemistry; Rabbits; Rats; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - metabolism; GFP; Glycogenin; Actin cytoskeleton; Glycogen metabolism; Green fluorescent protein
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(97)01299-4

We have studied the intracellular localization of glycogenin by fusing green fluorescent protein (GFP) to the N-terminus of rabbit muscle glycogenin and expressing the chimeric protein in C 2C 12, COS-1 and rat hepatic cells. The fusion protein showed a nuclear and cytosolic distribution and partially co-localized with actin in the cytosol. Disruption of the actin cytoskeleton with cytochalasin D led to a change in the pattern of green fluorescence, which coincided with that observed for the remaining non-depolymerized actin. The distribution of the single point mutant K324A was completely uniform and was not affected by this drug. These findings indicate that rabbit muscle glycogenin binds to actin through the heptapeptide 321DNIKKKL 327, a common motif found in other actin-binding proteins, which is located at the C-terminal end of this protein, and suggest that the actin cytoskeleton plays an important role in glycogen metabolism.