Isolation and characterization of a 30 kDa membrane glycoprotein from human stratum corneum

Using iodinated concanavalin A in conjunction with gel electrophoresis, we have identified a 30 kDa glycoprotein in the stratum corneum of human skin. We isolated this glycoprotein by extraction in nonionic detergent, affinity chromatography and preparative gel electrophoresis. It binds to concanavalin A but not to three other lectins. The purified glycoprotein migrates at 30 kDa whether or not reducing agents are present. It is rich in histidine and lysine, but lacks arginine, proline, tyrosine and methionine. It is clearly distinct from fillaggrin. We prepared a monospecific polyclonal antibody to this glycoprotein and localized it by immuno-histochemistry exclusively to the cell membrane of corneocytes. We postulate that the glycoprotein may play a role in the cohesion and desquamation of corneocytes.