Immunogen sequence: DVRTRPEVGE MLRNKLVRLM THLDTDVKRV AAEFLFVLCS ESVPRFIKYT GYGNAAGLLA ARGLMAGGRP EGQYSEDEDT DTDEYKEAKA SINPVTGRVE EKPPNPMEGM TEEQKEHEAM KLVTMFDKLS RNRVIQPMGM SPRGHLTSLQ DAMCETMEQQ LSSDPDSDPD. Guanine nucleotide exchange factor (GEF), whic