From Entangled Membranes to Eclectic Morphologies: Cubic Membranes As Subcellular Space Organizers

The identification of evolutionary conserved membrane morphologies whose architecture is governed by cubic symmetry--cubic membranes--adds a new dimension to cell membrane functions and, perspicuously, to their role in subcellular space organization. Through analysis of electron micrographs, three families of cubic membranes have been unequivocally identified in which one or more (parallel) membranes, described by periodic cubic surfaces, partition space into two or more independent, albeit convoluted, subspaces of membrane potential determined dimensions. The choice of a particular cubic symmetry is suggested to be due to its activity. Here the architecture and function of multiple (> or = 3) subspace organization in classical membrane bound organelles is addressed. As it can be precisely determined with cubic membranes suggests that they can be employed as a reference morphology.