A central small amino acid in the VAMP2 transmembrane domain regulates the fusion pore in exocytosis by Hastoy, B, Scotti, P, Milochau, A, Fezoua-Boubegtiten, Z, Rodas, J, Megret, R, Desbat, B, Laguerre, M, Castano, S, Perrais, D, Rorsman, P, Oda, R, Lang, J