Insulin prohormone processing, distribution, and relation to metabolism in Aplysia californica.
The first Aplysia californica insulin gene is characterized and its proteolytic processing from prohormone to final peptides elucidated using a combination of biochemical and mass spectrometric methods. Aplysia insulin (AI) is one of the largest insulins found, with a molecular weight of 9146 Da, and an extended A chain compared with other invertebrate and vertebrate insulins. The AI prohormone produces a series of C peptides and also a unique N-terminally acetylated D peptide. AI-producing cells are restricted to the central region of the cerebral ganglia mostly within the F and C clusters, and AI is transported to neurohemal release sites located on the upper labial and anterior tentacular nerves. The expression of AI mRNA decreases when the animal is deprived of food, and injections of AI reduce hemolymph glucose levels, suggesting that the function of insulin-regulating metabolism has been conserved.
Floyd
P D
PD
Department of Chemistry and the Beckman Institute, University of Illinois, Urbana, Illinois 61801, USA.
Li
L
L
Rubakhin
S S
SS
Sweedler
J V
JV
Horn
C C
CC
Kupfermann
I
I
Alexeeva
V Y
VY
Ellis
T A
TA
Dembrow
N C
NC
Weiss
K R
KR
Vilim
F S
FS
D000595:Amino Acid Sequence; D000818:Animals; D001048:Aplysia / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002096:C-Peptide / Q000737:chemistry / Q000235:genetics; D017952:Ganglia, Invertebrate / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000235:genetics*; D008195:Lymnaea; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009474:Neurons / Q000378:metabolism*; D010446:Peptide Fragments / Q000276:immunology; D011384:Proinsulin / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D002096:C-Peptide; D007328:Insulin; D010446:Peptide Fragments; D011384:Proinsulin