FIG. 1.

The ectodomain targets p10 for rapid degradation. (A) (Left) Transfected cells expressing full-length p10-2HAN were pulse-labeled and chased for the indicated times in minutes. Radiolabeled cells were solubilized in RIPA buffer or double-strength RIPA buffer, and p10 was immunoprecipitated with anti-p10 antiserum (α p10), resolved by SDS-PAGE, and visualized by fluorography. (Right) Same analysis with a control protein, the soluble sigma C protein of avian reovirus. (B) Full-length p10-2HAN (p10), p10ecto⁻ (ecto⁻), or p10e, with two N-terminal HA epitope tags (HA) and the cleavable HA signal peptide (SP), were expressed in transfected cells. The stability of the various p10 constructs was assessed by pulse-chase analysis as described for panel A. The nature of the various constructs is diagrammed at the bottom.