Figure 3: Crabp1-dependent activation of ERK1/2 by compounds 3 and 4 requires ligand binding. | Scientific Reports

Figure 3: Crabp1-dependent activation of ERK1/2 by compounds 3 and 4 requires ligand binding.

From: All trans-retinoic acid analogs promote cancer cell apoptosis through non-genomic Crabp1 mediating ERK1/2 phosphorylation

Figure 3

(A) Crabp1 expression assessed on protein (left) and mRNA (right) levels. (B) Western blot analysis. Compounds 3 and 4 fail to activate ERK1/2 in Crabp1-negative MOVCAR at 30 min, 100 nM. (C) Western blot analyses of kinetics of ERK1/2 activation by compounds (100 nM). MOVCAR cells re-expressing Crabp1 (upper panels) or empty vector (EV, lower panels) were treated with vehicle, RA, compound 3 or compound 4 for the indicated hrs. Early phase of ERK1/2 activation is detected in Crabp1 expressing cells. (D) Rapid ERK1/2 activation in MOVCAR re-expressing wild type or mock-mutated Crabp1 Y133F but no activation in cells re-expressing Crabp1 R131A, RA binding deficient mutant at 30 min, 100 nM treatments. (E) 3H-atRA ligand binding assay reveals RA binding to wild type and Crabp1 Y133F but no binding to Crabp1 R131A proteins. *p < 0.001 versus to control. Data is displayed as counts per minute (CPM). Data (A–E) are representative of at least 3 independent experiments.

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