Sqd interacts with the Drosophila retinoblastoma tumor suppressor Rbf.
The retinoblastoma tumor suppressor (RB) serves as a scaffold to coordinate binding of numerous proteins, including E2F and histone deacetylases, through its C-terminal domain. The amino-terminal half of RB has few known binding partners and its function is not well understood. We used the amino-terminal domain of the Drosophila retinoblastoma tumor suppressor Rbf (RbfN) to identify novel binding partners by immunoprecipitation coupled with mass spectrometry. Our experiment revealed that the RNA-binding protein Squid (Sqd) is a putative interacting partner of RbfN. Western blot confirmed that Sqd interacts with the amino-terminal domain of Rbf. We observed that Sqd colocalizes with RbfN in Drosophila salivary gland cells. We also show that double RNAi knockdown of Rbf and Sqd in the eye results in an extensive loss of eye bristles, suggesting that Rbf and Sqd function in a common pathway. We conclude from our studies that Rbf physically and genetically interacts with Sqd. We propose that the retinoblastoma tumor suppressor may play a novel role in RNA processing through interaction with RNA-binding proteins.
Department of Molecular and Cellular Biology, University of Arizona, Tucson, 85721, USA.
Joseph
J
Ahlander
Giovanni
G
Bosco
D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; D016601:RNA-Binding Proteins; C099965:Rbf protein, Drosophila; D016160:Retinoblastoma Protein; D014157:Transcription Factors; C081480:sqd protein, Drosophila