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[摘要]：The adaptor protein Cas contains a core substrate domain with Multiple YXXP motifs that are phosphorylated by Src and other tyrosine kinases. Here, we used a synthetic strategy to determine the importance of the arrangement, spacing, and identity of the YXXP motifs. By polymerizing short DNA sequences encoding two phosporylatlon motifs, we created a panel of Cas mutants in which the entire substrate domain was replaced by synthetic domains containing random numbers and arrangements of the motifs. Most of these synthetic Cas variants were recognized and phosphorylated by Src in vitro and in intact mammalian cells. The random polymer mutants also restored migration activity to Cas knock-out cells; even artificial proteins containing a single motif retained some biological. function.,Our results suggest that the arrangement of Cas motifs is not critical for signaling, This, Method could be used to identify the minimal functional units in other signaling proteins. |
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