The Hinge Region of Human Thyroid-Stimulating Hormone (TSH) Receptor Operates as a Tunable Switch between Hormone Binding and Receptor Activation
Figure 9
Involvement of TSHR-hinge region and hormone α-subunit in hormone mediated conformational change in TSHR.
Flow cytometric analysis of binding of 25 µg/ml of (9A.) MAb 311.62 or (9B.) MAb 311.82 to HEK293-hTSHR cells in absence of TSH (shaded solid line histogram) or pre-incubated with either 1 nM TSH (shaded dotted line histogram) or 25 nM TSH (shaded dashed line histogram). The culture supernatant of hormone α-subunit specific monoclonal antibody 2A6 was either added to HEK293-hTSHR cells previously incubated with (9C.) 25 nM TSH or (9D.) 25 nM TSH was added to HEK293-hTSHR cells previously exposed to similar concentration of 2A6 and binding of 2A6 to TSH in a TSH-TSHR complex was monitored in flow cytometry. All the flow cytometric experiments were carried out at 4°C to prevent hormone mediated receptor internalization.