Regulation of AKAP-membrane interactions by calcium.
The AKAP gravin is a scaffold for protein kinases, phosphatases, and adaptor molecules obligate for resensitization and recycling of beta2-adrenergic receptors. Gravin binds to the receptor through well characterized protein-protein interactions. These interactions are facilitated approximately 1000-fold when gravin is anchored to the cytoplasmic leaflet of the plasma membrane. Although the N-terminal region (approximately 550 residues) is highly negatively charged and probably natively unfolded, it could anchor gravin to the inner leaflet through hydrophobic insertion of its N-terminal myristate and electrostatic binding of three short positively charged domains (PCDs). Loss of the site of N-myristoylation was found to affect neither AKAP macroscopic localization nor AKAP function. Synthetic peptides corresponding to PCD1-3 bound in vitro to unilamellar phospholipid vesicles with high affinity, a binding reversed by calmodulin in the presence of Ca2+. In vivo gravin localization is regulated by intracellular Ca2+, a function mapping to the N terminus of the protein harboring PCD1, PCD2, and PCD3. Mutation of any two PCDs eliminates membrane association of the non-myristoylated gravin, the sensitivity to Ca2+/calmodulin, and the ability of this scaffold to catalyze receptor resensitization and recycling.
Tao
Jiangchuan
J
Department of Pharmacology, School of Medicine, Heath Sciences Center, State University of New York, Stony Brook, New York 11794-8651, USA.
Shumay
Elena
E
McLaughlin
Stuart
S
Wang
Hsien-yu
HY
Malbon
Craig C
CC
D054758:A Kinase Anchor Proteins; D000595:Amino Acid Sequence; D001692:Biological Transport; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D006801:Humans; D007424:Intracellular Fluid / Q000737:chemistry / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D008051:Lipid Bilayers / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D019814:Myristic Acid / Q000378:metabolism; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism; D055672:Static Electricity
D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D002147:Calmodulin; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; D018343:Receptors, Adrenergic, beta-2; D019814:Myristic Acid; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D017868:Cyclic AMP-Dependent Protein Kinases; D002118:Calcium