Comment on "Elastic Membrane Deformations Govern Interleaflet Coupling of Lipid-Ordered Domains"

In lieu of abstract, first paragraph reads: Galimzyanov et al. [1] find that line tension between thick liquid-ordered ($L_{o}$) and thinner liquid-disordered ($L_{d}$) registered lipid bilayer phases is minimised by an asymmetric "slip region", length $L\!\sim\!5\,\textrm{nm}$ (Fig. 1). They claim that line tensions alone explain domain registration, without "direct" (area-dependent) inter-leaflet interaction [2,3]. We show this is unfounded, without direct interaction their results would predict \textit{antiregistration}, dependent on composition. To find equilibrium from line energies, line \textit{tensions} must be combined with interfacial lengths for given states at given composition. This was not done in [1].