PMID: 19299457

 

    Legend: Gene, Sites

Title : A monoclonal antibody with thyrotropin ( TSH ) receptor inverse agonist and TSH antagonist activities binds to the receptor hinge region as well as to the leucine-rich domain

Abstract :
  1. Monoclonal antibody CS-17 is a TSH receptor ( TSHR ) inverse agonist (suppresses constitutive activity) and a TSH antagonist
  2. Elucidation of the CS-17 epitope will provide insight into TSHR structure and function
  3. Present information on its epitope conflicts with recent data regarding another TSHR inverse agonist antibody
  4. To characterize further the CS-17 epitope , we exploited the observation that CS-17 does not recognize a chimeric receptor with TSHR hinge region residues 261-289 replaced with homologous rat LH receptor residues (13 mismatches)
  5. We generated individual and double TSHR mutations corresponding to these mismatches
  6. On flow cytometry, only T273L/R274V reduced CS-17 recognition
  7. No mutation affected TSH-stimulated cAMP generation
  8. Because the immunogen for CS-17 generation was highly glycosylated, we also investigated whether the glycan moiety at N198 , topologically adjacent to Y195 (a previously identified epitopic component), could contribute to the CS-17 epitope
  9. Elimination of this N-linked glycan (mutations of N198 and T200 ) abrogated CS-17 binding without altering TSH responsiveness
  10. However, studies with tunicamycin suggested that these mutations affected CS-17 binding by altering the polypeptide backbone rather than eliminating the glycan moiety
  11. TSHR residues N198 and T200 , like Y195, are on the convex facet of the leucine-rich domain
  12. In summary, the present data indicate that the discontinuous epitope of CS-17, a TSHR inverse agonist and TSH antagonist, includes a component in the hinge region as well as the convex surface of the TSHR leucine-rich domain
  13. These findings expand our present concept of glycoprotein hormone binding and function
Output (sent_index, trigger, protein, sugar, site):
  • 13. glycoprotein, , glycoprotein, -, -
  • 8. N198, , -, the glycan moiety, N198
Output(Part-Of) (sent_index, protein, site):
  • 0. receptor, region
  • 11. TSHR, residues N198
  • 12. TSHR, domain
  • 4. TSHR, residues 261-289
  • 4. receptor, residues 261-289
  • 4. receptor, residues
*Output_Site_Fusion* (sent_index, protein, sugar, site):
  • 8. TSHR, the glycan moiety, N198

 

 

Protein NCBI ID SENTENCE INDEX
TSHR 25360 1,2,3,4,5,11,12
TSH receptor 25360 1