Involvement of HRD1 in disposal of membrane-tethered and soluble CD3-δ. (A) Radiolabeled CD3-δ was immunoisolated after the indicated chase times from wild-type MEFs (wt; lanes 1–3) or from MEFs lacking HRD1 (Hrd1^−/−; lanes 4–6). Relevant bands were quantified and plotted. (B) Same as described in A for CD3-δΔ. (C) Radiolabeled CD3-δΔ was immunoisolated after the indicated chase times from cells lacking HRD1 transfected with an empty plasmid (mock; lanes 1–3), a plasmid for expression of wild-type HRD1 (lanes 4–6), or a plasmid for expression of inactive HRD1 (HRD1*; lanes 7–9). Relevant bands were quantified and plotted. Molecular mass markers are shown on the left for all gels (given in kilodaltons).