Figure 6. Elevated ER stress in membralin KO mice.

(A) Upregulation of GRP78 and ATF4 in spinal cord of membralin KO mice. Left: immunoblot analysis shows higher levels of GRP78 and ATF4 in the spinal cord of P3 membralin KO mice compared to that of littermate WT mice. Right: increased expression level of GRP78 and ATF4 normalized to actin in membralin KO mice over WT mice. (B) Survival of MEFs after 24-hr exposure to tunicamycin or thapsigargin determined by a cytotoxicity assay. (C) The expression level of GRP78, CHOP, and ATF4 in MEFs from KO and WT mice is shown after exposure to tunicamycin at different time points. Levels of CHOP and ATF4 are elevated earlier and higher in MEFs from KO than that from WT mice. A representative immunoblot is shown; graphs include data from three experiments. For each panel, data are mean ± s.e.m.; n = 3 for each bar; *p < 0.05 by Student's t-test.

DOI: http://dx.doi.org/10.7554/eLife.06500.016

Figure 6—figure supplement 1. Membralin deletion does not alter Xbp-1 splicing.

(A) RT-PCR assay of Xbp-1 mRNA from brain and spinal cord from membralin WT and KO mouse. (B) RT-PCR assay of spliced and unspliced Xbp1 mRNA from membralin WT and KO MEF cells exposed to the ER stress inducer, tunicamycin (300 nM), for the indicated times.

DOI: http://dx.doi.org/10.7554/eLife.06500.017