FIGURE 6.

Constitutive transducin activation caused by the lack of GRK1 leads to induction of ER stress sensors and increase of protein ubiquitination similar to ARR1^−/−. A, retinas from dark-adapted mice (D) or mice exposed to 12 or 36 h of constant light or from mice exposed to light for 12 h and dark-adapted for 36 h (LD) were prepared for Western blots and probed with antibodies against GRP78, ATF3, ATF4, p-elf2α, IRE1α, ATF6, and actin. The levels of these proteins after a shorter time course of light exposure were also evaluated (3, 4, and 5 h). B, quantification of the protein levels for the indicated time courses (means ± S.E., n ≥ 3).