Delivering defined amounts of purified protein with high precision into living cells

Here, we detail a protocol using electroporation to precisely deliver defined amounts of purified protein into CAD cells. This method allows one million cells to be electroporated with protein simultaneously, with high delivery efficiency and low cell death. Further, by circumventing the normal biosynthetic pathway, proteins can be studied without the complication of post-translational modifications and before a transcriptional response can be initiated. This protocol will be useful for any researcher who is interested in protein concentration-dependent cellular phenotypes. For complete details on the use and execution of this protocol, please refer to Skruber et al. (2020).