L-cell growth stimulation by a beta-casein peptide: the importance of its phosphorylation site for activity.
L-cell proliferation was markedly enhanced by addition to the medium of a synthetic peptide corresponding to residues 1-18 of human beta-casein. Experiments using several synthetic peptides of decreasing length demonstrated that L-S-S-S-E-E (residues 7-12), a major phosphorylation site in beta-casein, appeared to be important for the activity. The phosphorylated beta-casein peptide showed no activity. Recent findings have demonstrated that a similar sequence, S-E-E-E or S-D-D-E, is commonly present in many oncoproteins derived from nuclear oncogenes such as myc, myb and E1A, and plays an important role in transformation functions. The beta-casein peptide may affect mammalian cell proliferation through a modification of of the oncoprotein functions.
Shimizu
M
M
Department of Agricultural Chemistry, University of Tokyo, Japan.
Kato
M
M
Miwa
K
K
Kaminogawa
S
S
D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000378:metabolism / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects*; D003470:Culture Media; D007739:L Cells; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism / Q000494:pharmacology*; D010766:Phosphorylation; D011402:Pronase / Q000378:metabolism; D013329:Structure-Activity Relationship
D002364:Caseins; D003470:Culture Media; D010446:Peptide Fragments; D011402:Pronase