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Crystal Structure of the Cytoplasmic Domain of the Type I TGFß Receptor in
Complex with FKBP12


Morgan Huse, Ye-Guang Chen, Joan Massagué, John Kuriyan

Cell, Vol. 96, 425-436, February 5, 1999

Activation of the type I TGFß receptor (TßR-I) requires phosphorylation of a regulatory segment known as the GS region, located upstream of the serine/threonine kinase domain in the cytoplasmic portion of the receptor. The crystal structure of a fragment of unphosphorylated TßR-I, containing both the GS region and the catalytic domain, has been determined in complex with the FK506-binding protein FKBP12. TßR-I adopts an inactive conformation that is maintained by the unphosphorylated GS region. FKBP12 binds to the GS region of the receptor, capping the TßR-II phosphorylation sites and further stabilizing the inactive conformation of TßR-I. Certain structural features at the catalytic center of TßR-I are characteristic of tyrosine kinases rather than Ser/Thr kinases.

Coordinates for the TGF-beta receptor-I complex with FKBP12 code: 1b6c.

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