Fig. 6: Illustration comparing an importin β-type NTR with an HIV-1 capsid.
From: HIV-1 capsids enter the FG phase of nuclear pores like a transport receptor
A typical importin β-type NTR is about 8 nm in diameter and is composed of HEAT repeats that not only capture cargo but also mediate multivalent FG interactions and passage through the FG phase of NPCs. The HIV-1 capsid is composed of pentameric and hexameric capsomeres. With a diameter of 60 nm, it would be too large to pass through the NPC scaffold in an NTR-chaperoned manner. Instead, it engages directly with FG contacts, ‘melting’ into the FG phase and allowing the encapsulated viral genome to cross the barrier without an exposure to the cytoplasmic antiviral surveillance machinery. Cohesive inter-FG interactions are shown as brown dots, NTR/capsid–FG interactions are shown in red.
