title: Adducin regulation. Definition of the calmodulin-binding domain and sites of phosphorylation by protein kinases A and C.
abstract: Adducin promotes association of spectrin with actin and caps the fast growing end of actin filaments. Adducin contains N-terminal core, neck, and C-terminal tail domains, is a substrate for protein kinases A (PKA) and C (PKC), and binds to Ca2+/calmodulin. Ser-726 and Ser-713 in the C-terminal MARCKS-related domains of alpha- and beta-adducin, respectively, were identified as the major phosphorylation sites common for PKA and PKC. PKA, in addition, phosphorylated alpha-adducin at Ser-408, -436, and -481 in the neck domain. Phosphorylation by PKA, but not PKC, reduced the affinity of adducin for spectrin-F-actin complexes as well as the activity of adducin in promoting binding of spectrin to F-actin. The myristoylated alanine-rich protein kinase C substrate-related domain of beta-adducin was identified as the dominant Ca2+-dependent calmodulin-binding site. Calmodulin-binding was inhibited by phosphorylation of beta-adducin and of a MARCKS-related domain peptide by PKA and PKC. Calmodulin in turn inhibited the rate, but not the extent, of phosphorylation of beta-adducin, but not alpha-adducin, by PKA and that of each subunit by PKC. These findings suggest a complex reciprocal relationship between regulation of adducin function by calmodulin binding and phosphorylation by PKA and PKC.
authors.affiliation: Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: C A
authors.initials: CA
authors.lastname: Hughes
authors.forename: V
authors.initials: V
authors.lastname: Bennett
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D010768:Phosphoserine / Q000032:analysis; D010769:Phosphothreonine / Q000032:analysis; D019000:Phosphotyrosine / Q000032:analysis; D011493:Protein Kinase C / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D000099291:Adducins
chemical_list: D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D003598:Cytoskeletal Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010446:Peptide Fragments; D010748:Phosphopeptides; D010768:Phosphoserine; D010769:Phosphothreonine; D019000:Phosphotyrosine; D011493:Protein Kinase C; D011506:Proteins; D000099291:Adducins; C000619710:MARCKS protein, human