Relationships Between Molecular Interactions (Nucleotides, Lipids and Proteins) and Structural Features of the Bovine Brain 21-kDa Protein


F. Schoentgen, Laboratoire des protéines, Centre National de la Recherche Scientifique Unité 1188, Université René Descartes, Pans 5, 45 rue des Saints-Pères, F-75270 Paris Cedex 06, France


A cytosolic 21-kDa protein isolated from bovine brain was demonstrated to bind hydrophobic ligands, particularly phosphatidylethanolamine. It was encountered in several tissues and species; however, its accurate function remained partially unknown. In order to obtain information from its structural features, we built a molecular model which revealed it to possess a nucleotide-binding site. In the present research, we describe the affinity of the bovine brain 21-kDa protein for nucleotides, and its association with cytosolic proteins, small GTP-binding proteins and lipid droplets. Our results suggest that, through its association with small GTP-binding proteins, the 21-kDa protein is implicated in signal mechanisms during cell growth and maturation.