Type IV Pili thumb|511x511px|Neisseria gonorrhoeae use their type IV pili as a motility structure. These are the steps for the type IV pilus twitching motility mechanism. Dynamic polymeric protein filaments called type IV pili allow N. gonorrhoeae to do many bacterial processes including adhesion to surfaces, transformation competence, twitching motility, and immune response evasions. To enter the host the bacteria uses the pili to adhere to and penetrate mucosal surfaces. The pili are a pivotal virulence factor for N. gonorrhoeae; without them, the bacterium is unable to promote colonization. For motility, individual bacteria use their pili in a manner that resembles a grappling hook: first, they are extended from the cell surface and attach to a substrate. Subsequent pilus retraction drags the cell forward. The resulting movement is referred to as twitching motility. N. gonorrhoeae is able to pull 100,000 times its own weight, and the pili used to do so are amongst the strongest biological motors known to date, exerting one nanonewton. The PilF and PilT ATPase proteins are responsible for powering the extension and retraction of the type IV pilus, respectively. The adhesive functions of the gonococcal pilus play a role in microcolony aggregation and biofilm formation. These pili are also used to avoid immune responses from the cell they are invading by having their type IV pili antigenically vary. The main pilus filament is replaced by variable DNA sequences very frequently. By doing this process rapidly, they are able to create a diversity of pili on their surface and evade the host cell's immune response.
Type IV Pili thumb|511x511px|Neisseria gonorrhoeae use their type IV pili as a motility structure. These are the steps for the type IV pilus twitching motility mechanism. Dynamic polymeric protein filaments called type IV pili allow N. gonorrhoeae to do many bacterial processes including adhesion to surfaces, transformation competence, twitching motility, and immune response evasions. To enter the host the bacteria uses the pili to adhere to and penetrate mucosal surfaces. The pili are a pivotal virulence factor for N. gonorrhoeae; without them, the bacterium is unable to promote colonization. For motility, individual bacteria use their pili in a manner that resembles a grappling hook: first, they are extended from the cell surface and attach to a substrate. Subsequent pilus retraction drags the cell forward. The resulting movement is referred to as twitching motility. N. gonorrhoeae is able to pull 100,000 times its own weight, and the pili used to do so are amongst the strongest biological motors known to date, exerting one nanonewton. The PilF and PilT ATPase proteins are responsible for powering the extension and retraction of the type IV pilus, respectively. The adhesive functions of the gonococcal pilus play a role in microcolony aggregation and biofilm formation. These pili are also used to avoid immune responses from the cell they are invading by having their type IV pili antigenically vary. The main pilus filament is replaced by variable DNA sequences very frequently. By doing this process rapidly, they are able to create a diversity of pili on their surface and evade the host cell's immune response.