The surface represents the combination of protein stability and folding kinetics required for it to be exported from the endoplasmic reticulum with minimum efficiency. Located in this space defined by protein folding and misfolding kinetics and thermodynamics are two points, which represent two variants of a protein: a mutant, which is outside the surface, and is therefore not exported efficiently enough for it to function, and the wild type, which is inside the surface and is exported normally.