Intermediate filament reconstitution in vitro. The role of phosphorylation on the assembly-disassembly of desmin.
Desmin, the myogenic intermediate filament protein, is a phosphoprotein containing phosphoserine, in vivo. The role of phosphorylation on assembly-disassembly and organization of the desmin filament has remained obscure. We report here on a stable and purified system which enables a biochemical examination of desmin filament assembly and disassembly. Using this in vitro system, we carried out stoichiometrical phosphorylations by purified protein kinases. The extent of polymerization-depolymerization was estimated using procedures related to centrifugation and electron microscopy. The evidence we obtained suggests that disassembly of the desmin filament and inhibition of the NaCl-dependent polymerization of the soluble desmin can reversibly occur with either cAMP-dependent or Ca2+-activated, phospholipid-dependent desmin phosphorylation.
Inagaki
M
M
Laboratory of Experimental Radiology, Aichi Cancer Center Research Institute, Japan.
Gonda
Y
Y
Matsuyama
M
M
Nishizawa
K
K
Nishi
Y
Y
Sato
C
C
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D002645:Chickens; D000242:Cyclic AMP / Q000494:pharmacology; D003893:Desmin / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D015636:Magnesium Chloride; D051379:Mice; D008854:Microscopy, Electron; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011108:Polymers; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D014746:Vimentin / Q000378:metabolism
D003893:Desmin; D010750:Phosphoproteins; D011108:Polymers; D014746:Vimentin; D015636:Magnesium Chloride; D010768:Phosphoserine; D012965:Sodium Chloride; D000242:Cyclic AMP; D011494:Protein Kinases; D011493:Protein Kinase C; D008274:Magnesium; D002118:Calcium