Figure 4.

CReP is a constitutively expressed short-lived protein. (A) Immunoblot of endogenous CReP, GADD34, and total eIF2α in untreated (UT), and tunicamycin (Tm, 2 μg/ml)- and arsenite-treated cells (As, 50 μM). (B) Autoradiogram of pulse chase–labeled endogenous CReP immunoprecipitated with an anti-CReP immune serum. The label in the CReP band is quantified with the signal at the end of the pulse set arbitrarily at 100 (Q). (C) Immunoblot of endogenous CReP, phosphorylated eIF2α and total eIF2α in cells treated with the protein synthesis inhibitor cycloheximide (CHX, 50 μg/ml).