A 17 AA signal peptide is required for the cell surface expression of LRRC32. a) Untransfected HEK293 cells or cells transfected with either C-terminus GFP-tagged LRRC32 or C-terminus GFP-tagged LRRC32 with a deleted signal peptide region were analyzed by flow cytometry for surface expression of LRRC32 or GFP expression. b) Anti-LRRC32 immunoblot analysis of total lysates from C-and N- terminus GFP-tagged LRRC32 expressing clones revealed intact LRRC32 expression at 99 kD (fusion protein: 29 kD GFP + 70 kD LRRC32) and 70 kD, respectively. However, immunoblot analysis of total lysates from C- terminus GFP-tagged LRRC32 expressing clones lacking an intact signal peptide did not detect the presence of LRRC32 (rightmost lane). c) RT-PCR analysis of HEK293 cell lysates utilizing untransfected, C-CAT, C-terminus GFP-tagged LRRC32, or C-terminus GFP-tagged LRRC32 lacking an intact signal peptide was performed using primers for Lrrc32 (left panel) or GFP (right panel).