VDAC-A Primal Perspective

The evolution of the eukaryotic cell from the primal endosymbiotic event involved a complex series of adaptations driven primarily by energy optimization. Transfer of genes from endosymbiont to host and concomitant expansion (by infolding) of the endosymbiont's chemiosmotic membrane greatly increased output of adenosine triphosphate (ATP) and placed selective pressure on the membrane at the host-endosymbiont interface to sustain the energy advantage. It is hypothesized that critical functions at this interface (metabolite exchange, polypeptide import, barrier integrity to proteins and DNA) were managed by a precursor beta-barrel protein (p beta B) from which the voltage-dependent anion-selective channel (VDAC) descended. VDAC's role as hub for disparate and increasingly complex processes suggests an adaptability that likely springs from a feature inherited from p beta B, retained because of important advantages conferred. It is proposed that this property is the remarkable structural flexibility evidenced in VDAC's gating mechanism, a possible origin of which is discussed.

Automated summary

The evolution of eukaryotic cells involved a series of complex adaptations primarily driven by energy optimization, resulting in increased ATP production and selective pressure. Critical functions at the host-endosymbiont interface were managed by a precursor beta-barrel protein (p beta B), giving rise to the voltage-dependent anion-selective channel (VDAC) with remarkable structural flexibility.