Photoaffinity labeling of dog pancreas microsomes with 8-azido-ATP inhibits association of nascent preprolactin with the signal sequence receptor complex.
Transport of bovine preprolactin into dog pancreas microsomes involves a microsomal protein which is sensitive to photoaffinity labeling with azido-ATP and which is distinct from the ATP-binding protein, immunoglobulin heavy chain binding protein. Here we addressed the question of what stage of preprolactin transport is affected. Thus a nascent presecretory protein which is related to preprolactin, termed ppl-86mer, was employed. Here we show that the nascent preprolactin did not become associated with the alpha-subunit of the signal sequence receptor complex after photoaffinity labeling of microsomes with azido-ATP. Therefore, we conclude that the microsomal protein which is sensitive to photoaffinity labeling with azido-ATP acts prior to the signal sequence receptor complex.
Zimmermann
R
R
Institut für Physiologische Chemie und Physikalische Biochemie, Universität München, Germany.
Zimmermann
M
M
Mayinger
P
P
Klappa
P
P
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000345:Affinity Labels / Q000494:pharmacology*; D000818:Animals; D001386:Azides / Q000494:pharmacology*; D001693:Biological Transport, Active; D004285:Dogs; D008861:Microsomes / Q000378:metabolism*; D010179:Pancreas / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000378:metabolism*; D011691:Puromycin / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid; D012261:Ribonucleoproteins / Q000378:metabolism
D000345:Affinity Labels; D001386:Azides; D011498:Protein Precursors; D021382:Protein Sorting Signals; D012261:Ribonucleoproteins; D011691:Puromycin; C017040:8-azidoadenosine 5'-triphosphate; C017671:preprolactin; D000255:Adenosine Triphosphate; D011388:Prolactin