Induction of cellular Herp expression by Luman. (A) Scanned image of a representative microarray used in the study. 293 cells were either transfected with pcLuman or the vector pcDNA3.1. cDNA samples were labeled with Alexa Fluor 555 or 647 and hybridized to the 1.7K human cDNA microarray. (B) Induction of Herp mRNA expression by Luman. Cells were transfected with pcLuman, pcLuman(N), or the vector only. Treatment with the ER stressor Tm was used as a positive control. Total RNA was extracted and subjected to Northern blot analysis using a DNA probe specific for Herp. The relative intensities of the bands were normalized against 18S rRNA, shown at the bottom. (C) Overexpression of Luman triggers its proteolytic cleavage. HeLa cells in 35-mm dishes were transfected with 1 μg of 3F-Luman, 3F-Luman(N), or the parental vector pcDNA3.1. For the positive control, cells were treated with brefeldin A (1 μg/ml) in the presence of MG132 (5 μM) for 5 h. The affinity-purified FLAG monoclonal antibody M2 (Sigma) was used as the primary antibody in the Western blotting. β-Actin was used as a loading control. Bands with an asterisk on the left are proteolysis products of full-length Luman and are labeled Luman40.