Background: PI(4,5)P 2 -and tyrosine phosphorylation-dependent unconventional secretion of FGF2 is mediated by direct translocation across the plasma membrane. Results: PI(4,5)P 2 -mediated membrane recruitment causes oligomerization of tyrosine-phosphorylated FGF2 that, in turn, triggers the formation of a lipidic membrane pore. Conclusion: Membrane-inserted FGF2 oligomers represent intermediates of membrane translocation during unconventional secretion. Significance: Mechanistic insight into a novel self-sustained mechanism of protein translocation across membranes is provided.

Background: FGF2 translocation across plasma membranes depends on phosphoinositide-dependent oligomerization and membrane pore formation. Results: Two unique surface cysteines are critical for efficient FGF2 oligomerization, membrane pore formation, and FGF2 secretion from cells. Conclusion: Formation of intermolecular disulfide bridges drives phosphoinositide-dependent FGF2 oligomerization at plasma membranes. Significance: A new cis element critical for unconventional secretion of FGF2 was identified and validated.

The existence and nature of an active chromosome segregation apparatus in bacteria has been a long-standing debate. A novel Brownian ratchet-type mechanism of chromosome segregation mediated by the Min system is identified in E. coli.