Functional Assessment of the Thyrotropin Receptor-β Subunit

I. Ciullo, R. Latif, P. Graves, T. F. Davies
2003 Endocrinology  
Posttranslational processing of the TSH receptor (TSHR) involves proteolysis of a single chain holoreceptor into TSHR-␣ (or A) and TSHR-␤ (or B) subunits, which remain associated via disulfide bonds and which may then form oligomers. As both uncleaved and cleavage-derived forms of this receptor have been reported to bind TSH and transduce signals, reasons for this cleavage into ␣and ␤-subunits have remained enigmatic. Recently we suggested that TSHR cleavage was related to receptor
more » ... ceptor oligomerization and now we have asked if cleavage influenced the binding of G proteins to this receptor. Furthermore, as TSHR-␣ subunits are subject to shedding from the cell surface membrane, we have examined whether the remaining TSHR-␤ subunits could mediate signaling themselves, either constitutively and /or ligand-induced. We found that only the Abbreviations: Ab, Autoantibody; CHO, Chinese hamster ovary; CM-DiI, lipophilic tracer carbocyanine; GFP, green fluorescent protein; TSHR, TSH receptor.
doi:10.1210/en.2002-220884 pmid:12810574 fatcat:zo2yilknz5a4pheh3usqoexfvu