- Hemidesmosome formation is initiated by the beta4 integrin subunit, requires complex formation of beta4 and HD1/plectin, and involves a direct interaction between beta4 and the bullous pemphigoid antigen 180. Schaapveld, R.Q., Borradori, L., Geerts, D., van Leusden, M.R., Kuikman, I., Nievers, M.G., Niessen, C.M., Steenbergen, R.D., Snijders, P.J., Sonnenberg, A. J. Cell Biol. (1998)