Editing Secretion (section)

==={{anchor|T2SS}}Type II secretion system (T2SS)===
{{Main|Type II secretion system}}
Proteins secreted through the type II system, or main terminal branch of the general secretory pathway, depend on the Sec or Tat system for initial transport into the [[periplasm]]. Once there, they pass through the outer membrane via a multimeric (12–14 subunits) complex of pore forming secretin proteins. In addition to the secretin protein, 10–15 other inner and outer membrane proteins compose the full secretion apparatus, many with as yet unknown function. Gram-negative [[Pilus#Type IV pili|type IV pili]] use a modified version of the type II system for their biogenesis, and in some cases certain proteins are shared between a pilus complex and type II system within a single bacterial species.