scholarly journals Calcium ion-stimulated phosphorylation of myelin proteins

1980 ◽  
Vol 186 (2) ◽  
pp. 469-473 ◽  
Author(s):  
P V Sulakhe ◽  
E H Petrali ◽  
B J Thiessen ◽  
E R Davis

Myelin isolated from the central and peripheral nervous system contains a Mg2+-dependent protein kinase that catalyses phosphorylation of myelin-specific proteins. This phosphorylation is markedly stimulated by Ca2+ but not by cyclic AMP. Evidence was obtained that suggested an involvement of calmodulin-like protein in the stimulatory effects of Ca2+ on myelin phosphorylation.

1984 ◽  
Vol 221 (2) ◽  
pp. 361-368 ◽  
Author(s):  
J M Bradbury ◽  
R J Thompson

Endogenous cyclic AMP-stimulated phosphorylation of a 49700-Mr Wolfgram protein component in rabbit central nervous system was investigated by using photoaffinity labelling and 2′,3′-cyclic nucleotide 3′-phosphodiesterase activity staining after electroblotting on to nitrocellulose paper. Photoaffinity labelling with 8′-azidoadenosine 3′,5′-cyclic monophosphate showed a cyclic AMP-binding protein that appeared to be intrinsic to the myelin membrane and appeared to represent the R-subunit of a type I cyclic AMP-dependent protein kinase. This photoaffinity-labelled protein was of larger apparent Mr than the protein showing cyclic AMP-stimulated phosphorylation. Blotting of one-dimensional sodium dodecyl sulphate/polyacrylamide-gel electrophoretograms followed by staining for 2′,3′-cyclic nucleotide 3′-phosphodiesterase activity showed two activity bands corresponding to the two components of the Wolfgram protein doublet. Cyclic AMP-stimulated protein phosphorylation corresponded to the upper component of this doublet. Electroblotting of two-dimensional non-equilibrium pH-gradient electrophoretograms also showed co-migration of cyclic AMP-stimulated protein phosphorylation with enzyme activity. It is proposed that central-nervous-system myelin contains an endogenous type I cyclic-AMP dependent protein kinase that phosphorylates the larger subunit of 2′,3′-cyclic nucleotide 3′-phosphodiesterase.


1984 ◽  
Vol 259 (1) ◽  
pp. 654-661 ◽  
Author(s):  
I H Majerfeld ◽  
B H Leichtling ◽  
J A Meligeni ◽  
E Spitz ◽  
H V Rickenberg

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