TABLE 1.

Overview of various models concerning the NPC, including the year of proposal, if applicable, and a comparative analysis of distinct characteristics. The abbreviation “n/c” denotes “not clear.”

Model and year proposed	Single or multiple channels for passive diffusion	Distinct passive and facilitated pathways	How do FG-Nups interact to form a selective barrier?	Does the scaffold change conformation?
Plug 1982	Multiple	n/c	n/c	n/c
Gradient 2001	n/c	Yes	Affinity gradient	n/c
Oily spaghetti 2001	Single	Yes	Hydrophobic	n/c
Selective phase/hydrogel 2001	Multiple	No	Hydrophobic	n/c
Polymer brush 2003	Single	Yes	Electrostatic	n/c
ROD 2005	Single	Yes	Hydrophobic	n/c
Forest 2010	Multiple	Yes	Hydrophobic/electrostatic	n/c
Dilation n/c	n/c	n/c	n/c	Yes
Transport receptor n/c	Single	Yes	Hydrophobic	n/c