I used the pDisplay vector to express my protein on the cell surface. I'm able to detect the protein on a western blot using anti-HA antibody, but not with immunofluorescence using anti-myc antibody. Can you please help troubleshoot?
We would recommend checking to make sure that the gene of interest is cloned in-frame with the Platelet-derived Growth Factor Receptor (PDGFR) transmembrane domain.
Can I use FACS cell sorting or magnetic bead-based methods to isolate my cells transfected with the pDisplay vector?
When we tried FACS cell sorting of pDisplay-transfected cells using our anti-myc antibody, the sorting was not very efficient. However, pDisplay-transfected cells can be isolated using magnetic beads by first incubating the cells with anti-myc antibody and then incubating the cell-antibody complex with magnetic beads that have anti-mouse IgG1 conjugated to them. The cell can then be isolated using a magnet.
Find additional tips, troubleshooting help, and resources within our Protein Expression Support Center.
I used pDisplay vector to express a cell surface receptor protein. Should I be concerned about digestion of the protein during trypsinization of the cells?
Trypsin digests proteins at arginine or lysine residues, and it is widely accepted that the extracellular domains of membrane proteins are digested upon trypsinization of cells. But typically these proteins are rapidly replaced once the trypsin is removed. As an alternative to trypsin, you can remove most adherent cells using Versene (Cat. No. 15040066), which is a sterile 0.5 mM EDTA solution in PBS, and/or scraping. The EDTA chelates any free Mg2+ or Ca2+ ions, which are necessary for maintaining many cell attachments. Cell Dissociation Buffer, Enzyme-free, Hank's-based (Cat. No. 13150016) or PBS-based (Cat. No. 13151014), which are cocktails of chelating agents, are also fine for this application and may be more effective than EDTA alone, and would be unlikely to adversely affect the receptor protein.
If I transfect empty pDisplay vector into mammalian cells, will it result in a cell membrane-targeted polypeptide?
Transfection of pDisplay vector alone into mammalian cells does not result in a displayed polypeptide because the Ig kappa signal peptide and the PDGFR transmembrane domain are not in the same reading frame, and the ORF containing the kappa signal peptide ends 5 bp before the start of what is defined as the PDGFR transmembrane domain.
I heard that you carry a vector to help secrete my protein so it is targeted to the cell membrane. Which one is it?
We offer the pDisplay vector, Cat. No. V66020, designed to target recombinant proteins to the surface of mammalian cells. It contains an N-terminal murine Ig kappa-chain secretion signal and a C-terminal transmembrane anchoring domain from Platelet-derived Growth Factor Receptor (PDGFR) to target and anchor the protein of interest to the cell surface.