Functional interaction of Sam68 and heterogeneous nuclear ribonucleoprotein K.

Sam68 is a target of the c-Src tyrosine kinase. We previously showed that overexpression of Sam68 functionally substitutes for, as well as synergies with, HIV-1 Rev in Rev-response element (RRE)-mediated gene expression and virus replication. Here we describe the identification of heterogeneous nuclear ribonucleoprotein K (hnRNP K) as a protein ...
that specifically interacts with Sam68 in vitro and in vivo. HnRNP K did not bind to RRE-RNA directly, but formed a super complex with Sam68 and RRE in vitro. RNase treatment did not change the strength of binding of hnRNP K to Sam68. We demonstrated that hnRNP K significantly inhibited Sam68-mediated, but not Rev-mediated, RRE-dependent gene expression. We further showed that Sam68, but not a non-functional mutant Sam68p21, inhibited transcriptional activation of CT element by hnRNP K. Interestingly, the Sam68p21 with a single amino acid substitution in the nuclear localization domain exhibited less affinity for hnRNP K in vitro. We propose that the direct interaction of Sam68 and hnRNP K adversely affect the activities of both proteins in signal transduction pathways of both transcriptional and post-transcriptional events.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Animals, COS Cells, Cells, Cultured, DNA-Binding Proteins, Dactinomycin, Gene Expression Regulation, Genes, env, Hela Cells, Heterogeneous-Nuclear Ribonucleoprotein K, Humans, Protein Binding, Protein Biosynthesis, Protein Processing, Post-Translational, RNA-Binding Proteins, Signal Transduction, Two-Hybrid System Techniques
Oncogene
Date: Oct. 17, 2002
Download Curated Data For This Publication
9703
Switch View:
  • Interactions 6