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VIP receptors in human SUP-T1 lymphoblasts
J Christophe1, A Cauvin, E Vervisch
1Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium.
Digestion
|January 1, 1990
Summary
Researchers identified novel vasoactive intestinal peptide (VIP) receptors on SUP-T1 lymphoma cells, detailing their specificity and desensitization mechanisms. These VIP receptors exhibit distinct characteristics in human lymphoblasts.
Area of Science:
- Pharmacology
- Cell Biology
- Endocrinology
Background:
- Vasoactive intestinal peptide (VIP) receptors play crucial roles in cellular signaling.
- Understanding VIP receptor characteristics is vital for comprehending cellular responses in various conditions, including cancer.
Purpose of the Study:
- To characterize the novel VIP receptors in the CD4+ Stanford University Pediatric (SUP)-T1 lymphoma cell line.
- To investigate the specificity and signaling pathways associated with these receptors.
Main Methods:
- Receptor occupancy assays using radiolabeled peptides [(125I)helodermin, (125I)(acetyl-His1)VIP].
- Adenylate cyclase activation assays in the presence of GTP and Gs activation.
- Analysis of receptor desensitization and downregulation upon peptide exposure.
Main Results:
- Helodermin demonstrated higher potency than (acetyl-His1)VIP, (Phe1)VIP, and VIP, while secretin was ineffective.
- Receptor selectivity decreased with permanent Gs activation.
- Rapid homologous desensitization and downregulation of VIP receptors were observed in intact cells.
Conclusions:
- VIP receptors coupled to adenylate cyclase exhibit distinct specificity in human SUP-T1 lymphoblasts.
- Receptor specificity is reduced upon permanent Gs activation.
- A rapid desensitization and downregulation process occurs, with partial resensitization independent of immediate protein synthesis.