Glucagon-like peptide-1(7–36)amide: characterization of the domain responsible for binding to its receptor on rat insulinoma RINm5F cells

Gallwitz, Baptist; Schmidt, WE; Conlon, J. M.; Creutzfeldt, W.

doi:10.1677/jme.0.0050033

Cited by 35 publications

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“…It is released postprandially from intestinal endocrine L cells and stimulates insulin secretion. Gallwitz et al (1990) have shown that the C-terminal fragment of the peptide is important for receptor binding of the hormone, but is not sufficient to transduce a biological action as does the intact peptide (raise in cyclic AMP levels in rat insulinoma RINm5F cells). It appears that as in the case of glucagon (Unson et al, 1989), of GIP (Schmidt et al, 1986(Schmidt et al, , 1987 and of other members of the VIP/glucagon peptide family (Christophe et al, 1989;Robberecht et al, 1992) also for GLP-1(7-36)amide an intact N-terminus is needed for signal transduction and biological action.…”

Section: Discussionmentioning

confidence: 99%

“…The truncated peptides could also be antagonists, because the binding specificity is directed by the C-terminal parts of these peptide hormones (Christophe et al, 1989;Gallwitz et al, 1990). Since the cleavage by this peptidase removes only 2 of 29-42 total residues of the hormones, antisera against these peptides not directed specially to the N-terminus should cross-react also with the truncated peptides.…”

Section: Discussionmentioning

confidence: 99%

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Dipeptidyl‐peptidase IV hydrolyses gastric inhibitory polypeptide, glucagon‐like peptide‐1(7–36)amide, peptide histidine methionine and is responsible for their degradation in human serum

Mentlein

Gallwitz

Schmidt

1993

European Journal of Biochemistry

1,083

655

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Anatomisches Institut andPeptides of the glucagodvasoactive-intestinal-peptide (VIP) peptide family share a considerable sequence similarity at their N-terminus. They either start with Tyr-Ala, His-Ala or His-Ser which might be in part potential targets for dipeptidyl-peptidase IV, a highly specialized aminopeptidase removing dipeptides only from peptides with N-terminal penultimate proline or alanine. Growthhormone-releasing factor(1-29)amide and gastric inhibitory peptidefglucose-dependent insulinotropic peptide (GIP) with terminal Tyr-Ala as well as glucagon-like peptide-1 (7 -36)amidehnsulinotropin [GLP-l(7 -36)amidel and peptide histidine methionine (PHM) with terminal His-Ala were hydrolysed to their des-Xaa-Ala derivatives by dipeptidyl-peptidase IV purified from human placenta. VIP with terminal His-Ser was not significantly degraded by the peptidase. The kinetics of the hydrolysis of GIP, GLP-1(7-36)amide and PHM were analyzed in detail. For these peptides K, values of 4-34 pM and V,,, values of 0.6-3.8 pmol . min-' . mg protein-' were determined for the purified peptidase which should allow their enzymic degradation also at physiological, nanomolar concentrations. When human serum was incubated with GIP or GLP-1(7-36)amide the same fragments as with the purified dipeptidyl-peptidase IV, namely the des-Xaa-Ala peptides and Tyr-Ala in the case of GIP or His-Ala in the case of GLP-1(7-36)amide, were identified as the main degradation products of these peptide hormones. Incorporation of inhibitors specific for dipeptidylpeptidase IV, 1 mM Lys-pyrrolidide or 0.1 mM diprotin A (Ile-Pro-Ile), completely abolished the production of these fragments by serum. It is concluded that dipeptidyl-peptidase IV initiates the metabolism of GIP and GLP-1(7-36)amide in human serum. Since an intact N-terminus is obligate for the biological activity of the members of the glucagonNIP peptide family [e. g. ) is known to be inactive to release insulin in the presence of glucose as does intact GIP], dipeptidylpeptidase-IV action inactivates these peptide hormones. The relevance of this finding for their inactivation and their determination by immunoassays is discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Dipeptidyl‐peptidase IV hydrolyses gastric inhibitory polypeptide, glucagon‐like peptide‐1(7–36)amide, peptide histidine methionine and is responsible for their degradation in human serum

Mentlein

Gallwitz

Schmidt

1993

European Journal of Biochemistry

1,083

655

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“…Although previous work suggested that the C-terminal segment of GLP-1 is important for efficient cAMP signaling via the GLP-1R (7,(17)(18)(19), the underlying mechanism(s) of action is poorly understood and may be a result of loss of either C-terminal helical structure, binding interactions, or both. To investigate the role of the C-terminal helical segment in GLP-1R signaling, a series of C-terminally truncated GLP-1 and Ex-4 peptides was produced.…”

Section: Design Of Truncated Glp-1 and Ex-4 Conotoxin Chimeras-mentioning

confidence: 99%

Truncated Glucagon-like Peptide-1 and Exendin-4 α-Conotoxin pl14a Peptide Chimeras Maintain Potency and α-Helicity and Reveal Interactions Vital for cAMP Signaling in Vitro

Swedberg

Schroeder

Mitchell

et al. 2016

Journal of Biological Chemistry

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Glucagon-like peptide-1 (GLP-1) signaling through the glucagon-like peptide 1 receptor (GLP-1R) is a key regulator of normal glucose metabolism, and exogenous GLP-1R agonist therapy is a promising avenue for the treatment of type 2 diabetes mellitus. To date, the development of therapeutic GLP-1R agonists has focused on producing drugs with an extended serum half-life. This has been achieved by engineering synthetic analogs of GLP-1 or the more stable exogenous GLP-1R agonist exendin-4 (Ex-4). These synthetic peptide hormones share the overall structure of GLP-1 and Ex-4, with a C-terminal helical segment and a flexible N-terminal tail. Although numerous studies have investigated the molecular determinants underpinning GLP-1 and Ex-4 binding and signaling through the GLP-1R, these have primarily focused on the length and composition of the N-terminal tail or on how to modulate the helicity of the full-length peptides. Here, we investigate the effect of C-terminal truncation in GLP-1 and Ex-4 on the cAMP pathway. To ensure helical C-terminal regions in the truncated peptides, we produced a series of chimeric peptides combining the N-terminal portion of GLP-1 or Ex-4 and the C-terminal segment of the helix-promoting peptide ␣-conotoxin pl14a. The helicity and structures of the chimeric peptides were confirmed using circular dichroism and NMR, respectively. We found no direct correlation between the fractional helicity and potency in signaling via the cAMP pathway. Rather, the most important feature for efficient receptor binding and signaling was the C-terminal helical segment (residues 22-27) directing the binding of Phe 22 into a hydrophobic pocket on the GLP-1R.Secretion of insulin is considerably higher in response to oral administration of glucose compared with intravenous delivery (1). This phenomenon, known as the "incretin effect," is primarily mediated by two peptide hormones called incretins: glucagon like peptide 1 (GLP-1) 5 (2) and glucose-dependent insulinotropic polypeptide (3). The incretin effect is often greatly reduced in patients suffering from type 2 diabetes mellitus (4), and a possible therapeutic approach for this condition is incretin supplement therapy. Because type 2 diabetes mellitus sufferers continue to respond to GLP-1, but not to glucose-dependent insulinotropic polypeptide (5), recent therapeutic supplement strategies have focused on GLP-1 and the development of synthetic analogs (6).GLP-1 exerts its physiological activity in the 0.1-1 nM range (7) by signaling through the glucagon-like peptide-1 receptor (GLP-1R), a secretin/family B of G protein-coupled receptors (GPCR) (8). Primary GLP-1R signaling occurs via binding to G ␣ subunits that activate the intracellular cAMP pathway. Additional signaling also occurs via both ␤-arrestin and mobilization of intracellular calcium. Indeed, the level of variability in response reflects the diverse physiological functions of GLP-1R in different tissues (9). As with other members of GPCR receptor family, the GLP-1R has a large extracellular N...

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“…Binding studies and determinations of CAMP production were carried out as previously described [13,141. Concentrations of CAMP were determined by a commercially available CAMP radioimmunoassay according to the manufacturer's instructions.…”

Section: Binding Studies and Determination Of Camp Productionmentioning

confidence: 99%

Structure/Activity Characterization of Glucagon‐Like Peptide‐1

Gallwitz

Witt

Paetzold

et al. 1994

European Journal of Biochemistry

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Glucagon-like peptide-1 is a gastrointestinal hormone that strongly stimulates insulin release via specific receptors on the pancreatic p-cell. To characterize the side-chain groups required for interaction of glucagon-like peptide-1 with its receptor, we performed binding studies with alanine-substituted glucagon-like peptide-1 analogues on RINmSF insulinoma cells. The binding affinity and biological activity of glucagon-like peptide-1 have been found to be sensitive to alanine exchanges in the N-terminal positions 1, 4, 6 and the C-terminal positions 22 and 23. Alanine substitutions at positions 5, 8, 10-12, 14, 16-21 and 25-30 do not change receptor affinity. These findings could be exploited to design glucagon-like peptide-1 agonists and probably antagonists for further physiological studies.Glucagon-like peptide-1 is a 30-residue gastrointestinal hormone released from the enteroglucagon cells (L-cells) in the small intestine [l -31. The post-translational processing of proglucagon in the small intestine leads to the generation of glucagon-like peptide-1, corresponding to positions 78 -108 of the human proglucagon precursor [3, 41. In v i m , glucagon-like peptide-1 increases insulin secretion from the isolated rat [S] and pig pancreas [2, 61, and from isolated rat islets [7]. In man, glucagon-like peptide-1 is released into the circulation postprandially, and glucagon-like peptide-1 infusions stimulate insulin release [ 81. Therefore, glucagon-like peptide-1 plays an important role in the postprandial regulation of insulin secretion. Recent studies have shown that glucagon-like peptide-1 also has an anti-diabetogenic effect by reducing the isoglycaemic meal-related requirement for insulin in patients with non-insulin-dependent diabetes mellitus [9][10][11].Receptors for glucagon-like peptide-1 have been characterized in RINm5F cells [12-141, a Abbreviations. Fmoc, N-9-fluorenylmethoxycarbonyl; [HlAIglucagon-like peptide-1 , glucagon-like peptide-I , with an alanine exchange in position 1 for the naturally occurring histidine residue. All other glucagon-like peptide-1 analogues are named accordingly with the first letter giving the naturally occurring amino acid in the glucagon-like peptide-1 sequence and the number following the first letter giving the position of the exchanged amino acid.Note. This work is dedicated to Werner Creutzfeldt, Professor emeritus of Medicine, Georg-August University of Gottingen, Germany, on the occasion of his 70th birthday. the gene encoding the receptor has been localized in humans [17]. So far, little is known about the structural requirements for glucagon-like peptide-1 binding to its receptor. Binding studies with N-terminal and C-terminal glucagon-like peptide-1 fragments have shown that the C-terminal domains of the glucagon-like peptide-1 molecule are important for receptor binding. The N-terminal fragment glucagon-like peptide-1 (7 -2.5) did not show receptor binding, indicating that longer N-terminal fragments are needed for receptor recognition [ 1 31. The glucag...

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Glucagon-like peptide-1(7–36)amide: characterization of the domain responsible for binding to its receptor on rat insulinoma RINm5F cells

Cited by 35 publications

References 0 publications

Dipeptidyl‐peptidase IV hydrolyses gastric inhibitory polypeptide, glucagon‐like peptide‐1(7–36)amide, peptide histidine methionine and is responsible for their degradation in human serum

Dipeptidyl‐peptidase IV hydrolyses gastric inhibitory polypeptide, glucagon‐like peptide‐1(7–36)amide, peptide histidine methionine and is responsible for their degradation in human serum

Truncated Glucagon-like Peptide-1 and Exendin-4 α-Conotoxin pl14a Peptide Chimeras Maintain Potency and α-Helicity and Reveal Interactions Vital for cAMP Signaling in Vitro

Structure/Activity Characterization of Glucagon‐Like Peptide‐1

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