Phosphorylation of neurofilament proteins by protein kinase C.
The low molecular mass (70 kDa) subunit of neurofilaments (NF-L) contains at least three phosphorylation sites in vivo and is phosphorylated by multiple kinases in a site-specific manner [(1987) J. Neurochem. 48, S101; Sihag, R.K. and Nixon, R.A. submitted]. In this study, we observed that the three subunits of neurofilament proteins from retinal ganglion cell neurons are substrates for purified mouse brain protein kinase C. Two-dimensional alpha-chymotryptic phosphopeptide map analyses of the NF-L subunit demonstrated that protein kinase C phosphorylates four polypeptide sites, two of which incorporate phosphate when retinal ganglion cells are pulse-radiolabeled with [32P]orthophosphate in vivo.
Sihag
R K
RK
Ralph Lowell Laboratories, McLean Hospital, Belmont, MA 02178.
Jeng
A Y
AY
Nixon
R A
RA
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000201:enzymology; D002918:Chymotrypsin; D005260:Female; D006493:Heparin / Q000494:pharmacology; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010710:Phosphates / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000032:analysis / Q000378:metabolism
D007381:Intermediate Filament Proteins; D010710:Phosphates; D000255:Adenosine Triphosphate; D006493:Heparin; D011493:Protein Kinase C; D002918:Chymotrypsin