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Nature. 1993 Aug 12;364(6438):648-52.

A retinoblastoma-binding protein related to a negative regulator of Ras in yeast.

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Center for Molecular Medicine, University of Texas, Health Science Center, San Antonio 78245-3207.


The growth suppression function of the retinoblastoma protein (Rb) is though to be mediated by Rb binding to cellular proteins. p48 is one of the major proteins that binds to a putative functional domain at the carboxy terminus of the Rb protein. Here we report the isolation of a full-length complementary DNA (RbAp48) encoding p48. Complex formation between p48 and Rb occurs in vitro and in vivo, and apparently involves direct interaction between the proteins. Like Rb, p48 is a ubiquitously expressed nuclear protein. RbAp48 share sequence homology with MSI1, a negative regulator of the Ras-cyclic AMP pathway in the yeast Saccharomyces cerevisiae. Furthermore, like MSI1, human RbAp48 suppresses the heat-shock sensitivity of the yeast ira1 strains and RAS2Val19 strains. Interaction with p48 may be one of the mechanisms for suppression of growth mediated by Rb.

[Indexed for MEDLINE]

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