Is receptor cleavage into two subunits necessary for thyrotropin action?

GD Chazenbalk, SM McLachlan, Y Nagayama… - Biochemical and …, 1996 - Elsevier
GD Chazenbalk, SM McLachlan, Y Nagayama, B Rapoport
Biochemical and biophysical research communications, 1996Elsevier
Unlike the wild-type thyrotropin (TSH) receptor, the chimeric TSH-LH/CG receptor TSH-LHR-
14 does not cleave into two subunits when cross-linked to [125I] TSH on the surface of intact
cells. Immunoblotting of TSH-LHR-14 in whole cell homogenates demonstrated that only a
single chain receptor was detected under reducing conditions. TSH-LHR-14, like the A
subunit of another chimeric receptor (TSH-LHR-10) thatdoescleave into two subunits, was
almost entirely resistant to endoglycosidase H, indicating that it contains predominantly …
Unlike the wild-type thyrotropin (TSH) receptor, the chimeric TSH-LH/CG receptor TSH-LHR-14 does not cleave into two subunits when cross-linked to [125I]TSH on the surface of intact cells. Immunoblotting of TSH-LHR-14 in whole cell homogenates demonstrated that only a single chain receptor was detected under reducing conditions. TSH-LHR-14, like the A subunit of another chimeric receptor (TSH-LHR-10) thatdoescleave into two subunits, was almost entirely resistant to endoglycosidase H, indicating that it contains predominantly complex carbohydrate. The fact that TSH-LHR-14 reaches the cell surface where it binds TSH with high affinity and transduces a signal indicates that receptor cleavage into two subunits is not a prerequisite for TSH action.
Elsevier