Diagram of a voltage-sensitive sodium channel α-subunit. G - glycosylation, P - phosphorylation, S - ion selectivity, I - inactivation, positive (+) charges in S4 are important for transmembrane voltage sensing
John Schmidt
CC BY-SA 3.0
<p><span class="int-own-work" lang="en">Own work</span>
</p>
I (John Schmidt) made this diagram for Wikipedia based on <a rel="nofollow" class="external text" href="http://courses.cm.utexas.edu/jrobertus/ch339k/overheads-2/ch12_volt-gated-chan.jpg">Overview of the voltage-gated sodium channel family</a>.