Involvement of HRD1 and GP78 in disposal of soluble and membrane-tethered NHK variants. (A) Radiolabeled NHK was immunoisolated after the indicated chase times from cells expressing a scrambled siRNA (siSCR; lanes 1–3), an siRNA targeting HRD1 (siHRD1; lanes 4–6), GP78 (siGP78; lanes 7–9), or both HRD1 and GP78 (siHRD1/siGP78; lanes 10–12). Relevant bands were quantified and plotted. (B and C) Same as described in A for NHK_BACE and NHK_CD3δ, respectively. Molecular mass markers are shown on the left for all gels (given in kilodaltons).