Production of three GPR110 isoforms in human cell lines. (A) HA-tagged isoforms 1-3 were transiently expressed in HEK (lane1), HeLa (lane 2), and prostate line PC-3 (lane 3). Protein production detected by immunoblot with HA.11 antibody, which is specific to the HA tag; protein ladder molecular weights at the far left, in kD. Arrows point to the two major 80 and 100 kD molecular weight bands of isoform 1; and to a 30 kD band, representing a putative cleaved product. (B) isoforms 2 and 3, and (C) the four HA tagged isoform 1 proteins in HEK lysates (L) treated with (+) or without (-) glycosidase PNGaseF. Cterm, C-terminal HA-tagged isoform 1. Arrows point to the two major 60 and 75 kD bands after glycosidase treatment; and to a putative SEA cleavage product (in dotted box).