title: A possible role of the phosphorylation of synaptic membrane proteins in the control of calcium ion permeability.
abstract: Incubation of synaptosomes under conditions which result in complete phosphorylation of membrane bound accepter proteins does not affect the permeability to Na+ or K+ as measured by a spectrophotometric method. This technique was not, however, sensitive enough to determine permeability to Ca2+ which was thus estimated, using 45Ca2+. It was found that although phosphorylation did not affect the equilibrium binding of 45Ca it did lower the rate of both Ca2+ uptake and efflux. The most likely interpretation of these results is that phosphorylation of proteins in the synaptic membrane lowers the permeability of the membrane to Ca2+. This could have a role in the regulation of synaptic transmission.
mesh_terms: D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D051381:Rats; D012964:Sodium / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D010710:Phosphates; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium