Identification of targets for calcium signaling through the copine family of proteins. Characterization of a coiled-coil copine-binding motif.
We provide evidence that copines, members of a ubiquitous family of calcium-dependent, membrane-binding proteins, may represent a universal transduction pathway for calcium signaling because we find copines are capable of interacting with a wide variety of "target" proteins including MEK1, protein phosphatase 5, and the CDC42-regulated kinase, that are themselves components of intracellular signaling pathways. The copine target proteins were identified by yeast two-hybrid screening and the interactions were verified in vitro using purified proteins. In the majority of cases the copine binds to a domain of the target protein that is predicted to form a characteristic coiled-coil. A consensus sequence for the coiled-coil copine-binding site was derived and found to have predictive value for identifying new copine targets. We also show that interaction with copines may result in recruitment of target proteins to membrane surfaces and regulation of the enzymatic activities of target proteins.
Tomsig
Jose Luis
JL
Department of Pharmacology, University of Virginia, Charlottesville 22908, USA.
Snyder
Sandra L
SL
Creutz
Carl E
CE
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D020013:Calcium Signaling / Q000502:physiology*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D048369:MAP Kinase Kinase 1; D008274:Magnesium / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; C110203:copine; D017346:Protein Serine-Threonine Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D008274:Magnesium