Blocked flu virus ion channel, artwork. This ion channel is an M2 membrane ion channel, found in the membranes of flu viruses. Here, a molecule of the anti-viral drug adamantane (blue) is blocking the ion channel. One of the functions of the M2 ion channel is to allow protons (hydrogen ions) into the virus, triggering the release of its genetic material. This is a vital stage in the viral replication and infection cycle, and stopping the ion channels from functioning is how anti-viral drugs like adamantane work. Viral membrane proteins (red and yellow) are seen in the background.