Elucidation of the membrane and metal binding interface of Nup214/Nup88 sub complex of the nuclear pore complex

Abstract

The nuclear pore complex (NPC) is a large megadalton assembly that functions as an exclusive gateway between the nucleus and the cytoplasm, responsible for bidirectional nucleocytoplasmic transport. The NPC is composed of 32 to 34 different types of proteins known as nucleoporins (Nups) that are present in multiple copies (8, 16, 32, or up to 48). These Nups assemble together to form highly modular assembly structures that can range from ~60 to ~120 MDa in yeast and humans respectively. These Nups are found to be arranged in various subcomplexes like the cytoplasmic ring complex (CR), the inner ring complex (IR), the central transport channel (CTC), the nuclear ring complex (NR), and the Y-complex. Among them, the CR complex, containing the Nup88·Nup62·Nup214 complex is exclusively involved in mRNA transport, by virtue of its positioning over the CTC. Understanding the interactions of these Nups with each other as well as the nuclear membrane is vital to understand assembly as well as functioning of the NPC. Central to the interactions are the betapropellor domains of Nup88 and Nup214. Here we report purification of these two subunits in vitro and attempts for purification of their complex. We further performed in silico analysis of these subunits to determine their membrane binding propensity, interaction strength, as well as metal binding potential.