Abstract
Biotin identification (BioID) proteomics facilitates the unbiased detection of protein interaction neighborhoods in live cells. The BioID technique relies on the covalent biotin alteration of vicinal proteins by a modified bacterial biotin ligase. The biotin ligase is fused to a protein of interest to identify putative protein-protein interactions. Here, we describe the adaptation of this technique for use in three-dimensional epidermal cultures. Due to the covalent biotin modification of proteins, our protocol allows for the complete solubilization of the total cellular protein content in differentiated keratinocytes. Thus, a comprehensive network of potential interactors of a protein of interest can be mapped.