Immunogen sequence: ELKRNFMEST PEPRPNEWEK RRITPLSLQT QGSSHETLNI VEEKKRAEVG KDERVITEEE VEEE. The 4.1 gene family encodes a group of multifunctional cytoskeletal proteins (4.1R, 4.1G, 4.1N and 4.1B), which are predominantly expressed in the nervous system.