Does phosphorylase kinase control glycogen biosynthesis in skeletal muscle?
Immunoblotting as well as enzyme assays demonstrate the presence of the self-glucosylating protein, glycogenin, in the protein-glycogen complex, in the sarcoplasmic reticulum and in phosphorylase kinase. In all three compartments glycogenin occurs in different, albeit, defined glucosylated forms, which upon deglucosylation are converted into a 42 kDa form. We suggest that phosphorylase kinase might have a dual function in glycogen biogenesis: firstly, control of glycogen degradation in the protein-glycogen complex via phosphorylation of glycogen phosphorylase b; secondly, regulation of glycogen biosynthesis on the sarcoplasmic reticular membranes via phosphorylation and thereby inhibition of glycogen synthase.
Polishchuk
S V
SV
Abteilung für Biochemie Supramolekularer Systeme, Ruhr-Universität Bochum, Germany.
Brandt
N R
NR
Meyer
H E
HE
Varsányi
M
M
Heilmeyer
L M
LM
D000818:Animals; D005947:Glucose / Q000378:metabolism; D005964:Glucosyltransferases; D006003:Glycogen / Q000096:biosynthesis* / Q000737:chemistry; D006006:Glycogen Synthase / Q000378:metabolism; D006023:Glycoproteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D010764:Phosphorylase Kinase / Q000737:chemistry / Q000378:metabolism*; D010763:Phosphorylase b / Q000378:metabolism; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000737:chemistry / Q000201:enzymology
D006023:Glycoproteins; C051887:glycogenin; D006003:Glycogen; D005964:Glucosyltransferases; D010763:Phosphorylase b; D006006:Glycogen Synthase; D010764:Phosphorylase Kinase; D005947:Glucose