Proteolytic processing of the Aplysia egg-laying hormone prohormone.
By using matrix-assisted laser desorption/ionization time-of-flight MS, individual peptidergic neurons from Aplysia are assayed. A semiquantitative method is developed for comparing single-cell profiles by using spectral normalization, and peptides are localized to specific cells by mass spectrometric cell mapping. In addition to all previously identified products of the egg-laying hormone (ELH) gene, other peptides are formed from proteolytic hydrolysis of Leu-Leu residues within ELH and acidic peptide (AP). AP exhibits further processing to yield AP1-20 and AP9-27. These peptides appear to be colocalized in vesicles with ELH, transported to specific neuronal targets, and released in a Ca2+-dependent manner. A differential peptide distribution is observed at a specific target cell, and a low-frequency variation of AP, [Thr21]AP, is detected in a single animal.
Garden
R W
RW
Department of Chemistry and Beckman Institute, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
Shippy
S A
SA
Li
L
L
Moroz
T P
TP
Sweedler
J V
JV
D000818:Animals; D001048:Aplysia; D002118:Calcium / Q000378:metabolism; D006868:Hydrolysis; D007447:Invertebrate Hormones / Q000032:analysis* / Q000378:metabolism; D013058:Mass Spectrometry; D009474:Neurons / Q000378:metabolism*
D007447:Invertebrate Hormones; C026880:egg-laying hormone, Mollusca; D002118:Calcium