Synthetic amphipathic peptides resembling apolipoproteins stimulate the release of human placental lactogen.
Previous studies from our laboratory demonstrated native high density lipoproteins and apolipoproteins AI, AII, and CI, stimulate the release of human placental lactogen (hPL) from trophoblast cells in culture. To examine the mechanisms by which these apolipoproteins stimulate hPL release, we have studied hPL secretion in response to several synthetic peptide analogs of the amphipathic helical structure of the apolipoproteins. The magnitude of the stimulation of hPL release in response to the analog peptides correlated with the ability to displace apolipoproteins from high density lipoprotein and with other measures of phospholipid binding affinity such as the increase in alpha-helicity and the size of complexes formed between the peptide and phospholipid. The correlation of stimulatory ability and lipid affinity suggests that the action of the apolipoproteins on hPL release may be mediated through an interaction with plasma membrane phospholipids.
Jorgensen
E V
EV
Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710.
Anantharamaiah
G M
GM
Segrest
J P
JP
Gwynne
J T
JT
Handwerger
S
S
D000595:Amino Acid Sequence; D001053:Apolipoproteins / Q000378:metabolism / Q000494:pharmacology*; D002478:Cells, Cultured; D004134:Dimyristoylphosphatidylcholine; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D010928:Placental Lactogen / Q000378:metabolism*; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D014327:Trophoblasts / Q000378:metabolism
D001053:Apolipoproteins; D010455:Peptides; D010928:Placental Lactogen; D004134:Dimyristoylphosphatidylcholine