title: Investigation into the mechanism regulating MRP localization.
abstract: The major PKC substrates MARCKS and MacMARCKS (MRP) are membrane-binding proteins implicated in cell spreading, integrin activation and exocytosis. According to the myristoyl-electrostatic switch model the co-operation between the myristoyl moiety and the positively charged effector domain (ED) is an essential mechanism by which proteins bind to membranes. Loss of the electrostatic interaction between the ED and phospholipids, such as Ptdins(4,5)P2, results in the translocation of such proteins to the cytoplasm. While this model has been extensively tested for the binding of MARCKS far less is known about the mechanisms regulating MRP localization. We demonstrate that after phosphorylation, MRP is relocated to the intracellular membranes of late endosomes and lysosomes. MRP binds to all membranes via its myristoyl moiety, but for its localization at the plasma membrane the ED is also required. Although the ED of MRP can bind to Ptdins(4,5)P2 in vitro, this binding is not essential for its retention at or targeting to the plasma membrane. We conclude that the co-operation between the myristoyl moiety and the ED is not required for the binding to membranes in general but that it is essential for the targeting of MRP to the plasma membrane in a Ptdins(4,5)P2-independent manner.
authors: Division of Cell Biology, Netherlands Cancer Institute, 121 Plesmanlaan, 1066 CX Amsterdam, The Netherlands.
authors: Iman
authors: I
authors: van den Bout
authors: Jacco
authors: J
authors: van Rheenen
authors: Annelies A
authors: AA
authors: van Angelen
authors: Johan
authors: J
authors: de Rooij
authors: Kevin
authors: K
authors: Wilhelmsen
authors: Kees
authors: K
authors: Jalink
authors: Nullin
authors: N
authors: Divecha
authors: Arnoud
authors: A
authors: Sonnenberg
mesh_terms: D000818:Animals; D001665:Binding Sites; D002148:Calmodulin-Binding Proteins; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004705:Endocytosis; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins; D009154:Mutation; D009226:Myristates / Q000378:metabolism; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport
chemical_list: D002148:Calmodulin-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C000619710:MARCKS protein, human; C000619711:Marcks protein, mouse; C512945:Marcksl1 protein, mouse; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009226:Myristates; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D000076250:Myristoylated Alanine-Rich C Kinase Substrate