Progesterone Receptor Membrane Component 1 Is a Functional Part of the Glucagon-like Peptide-1 (GLP-1) Receptor Complex in Pancreatic β Cells

Abstract

Glucagon-like peptide-1 (GLP-1Glucagon-like peptide-1 (GLP-1) 1 is a gastrointestinal hormone secreted by intestinal L cells upon food intake that is best known for its role in controlling glucose homeostasis. 1 The abbreviations used are: GLP-1, glucagon-like peptide-1; GLP-1R, glucagon-like peptide-1 receptor; AP-MS, affinity purificationmass spectrometry; cAMP, cyclic adenosine monophosphate; CAV1, caveolin-1; CHO, Chinese hamster ovary; co-IP, co-immunoprecipitation; EGFR, epidermal growth factor receptor; EPAC, exchange protein directly activated by cAMP; FRET, fluorescence resonance energy transfer; GIIS, GLP-1-induced insulin secretion; GSIS, glucose-stimulated insulin secretion; HTRF, homogeneous time-resolved fluorescence; INS1, rat pancreatic ␤ cell; MIN6, mouse pancreatic ␤ cell; MYTH, membrane-based split-ubiquitin yeast two-hybrid; P4, progesterone; PGRMC1, progesterone receptor membrane component 1; PCC, Pearson's correlation coefficient; PI3K, phosphoinositide 3-kinase; Rab5b, Ras-related protein Rab-5B; Rab5c, Ras-related protein Rab-5; RC2, GLP-1R-His-V5 stable expressed Chinese hamster ovary; RP8, Rp-8-bromo-␤-phenyl-1,N2-ethenoguanosine3,5-cyclic monophosphorothioate sodium salt hydrate. Research

The Identification of Novel Protein-Protein Interactions in Liver that Affect Glucagon Receptor Activity

“…Interestingly, some of the proteins such as CAV1 and PGRMC1 were previously found to interact with GLP-1R [17, 26]. We also performed functional enrichment analysis using the David bioinformatics tool.…”

“…The percentage of specific binding was calculated by subtracting the unspecific binding intensities from the control group [17]. The E:I ratio was used to estimate the binding strength/percentage of interactors to GCGR ( Fig 3B ).…”

A Novel GLP1 Receptor Interacting Protein ATP6ap2 Regulates Insulin Secretion in Pancreatic Beta Cells

“…ATP6ap2 has been shown to be expressed in several tissue including brain, heart, kidney, liver, pancreas, and adipose tissues (43,44) with the highest levels reported in MIN6 cells (BioGPS (46, 47)). To localize ATP6ap2 expression within the pancreas, both immunohistochemistry and immunofluorescence staining were performed on mouse pancreatic slices and dispersed human islet cells, respectively.…”

“…Total RNA from cells was prepared using the RNeasy mini kit (Qiagen) according to the manufacturer's instructions. Purified RNA was converted to cDNA using a Moloney murine leukemia virus reverse transcriptase cDNA kit (Sigma), and real time PCR was performed using an ViiA7 real time PCR system (Applied Biosystems, Foster City, CA) according to the same protocol described in previous studies (43). A standard curve was generated using mouse genomic DNA for quantification purposes.…”

“…Glucose-stimulated Insulin Secretion and Intracellular cAMP Assays-Glucose-stimulated insulin secretion (GSIS) studies were carried out as previously described (43). Briefly, cells were preincubated for 2 h in 2.5 mM glucose HEPES balanced salt solution (114 mm NaCl, 4.7 mm KCl, 1.2 mm KH 2 PO 4 , 1.16 mM MgSO 4 , 2.5 mM CaCl 2 , 25.5 mm NaHCO 3 , 20 mm HEPES, and 0.2% (w/v) bovine serum albumin, essentially fatty-acid free, pH7.2) and then in the same HEPES balanced salt solution buffer containing different indicated glucose concentrations for 1 h with 30 nM GLP1 (GLP1-induced insulin secretion) (Bachem Inc., Torrance, CA).…”