Related Experiment Video
Updated: Sep 7, 2026

Titration ELISA as a Method to Determine the Dissociation Constant of Receptor Ligand Interaction
Published on: February 15, 2018
Removal of domain D2 or D3 of the human urokinase receptor does not affect ligand affinity
L Riittinen1, P Limongi, M P Crippa
1Department of Biology and Biotechnology (DIBIT), San Raffaele Scientific Institute, Milan, Italy.
Abstract:
The main ligand-binding determinant of the human urokinase receptor (uPAR) is located in the amino terminal domain D1, but when isolated this domain presents a 1500 fold lower affinity than the intact three-domain uPAR (D1D2D3). uPAR mutants missing either domain 2 (D1HD3) or domain 3 (D1D2) were expressed in murine LB6 cells and showed to be properly GPI-anchored to the cell surface. Binding assays with [125I]ATF demonstrated that these mutants possessed a normal (D1D2) or slightly reduced (D1HD3) affinity, indicating that a high ligand-affinity may be achieved by a combination of D1 with domain D2 or D3.
Related Concept Videos
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Ligand Binding and Linkage
Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
GPCR Desensitization
Transducer Mechanism: Enzyme-Linked Receptors
Major types that are helpful drug targets include:
The Two-State Receptor Model
The binding affinity of a drug determines its interaction with one...

