Membrane-coating lattice scaffolds in the nuclear pore and vesicle coats: commonalities, differences, challenges

NC Leksa, TU Schwartz - Nucleus, 2010 - Taylor & Francis
NC Leksa, TU Schwartz
Nucleus, 2010Taylor & Francis
The nuclear pore complex (NPC) regulates all traffic between the cytoplasm and the
nucleus. It is a large protein assembly composed of multiple copies of~ 30 nucleoporins
(nups). Structural studies of the NPC have been limited by its considerable size and
complexity. Progress toward understanding the structure of this nanomachine has benefited
from its modular nature, which allows for this 40-60 MDa assembly to be broken down into
subcomplexes that can be studied individually. While recent work by both crystallographers …
The nuclear pore complex (NPC) regulates all traffic between the cytoplasm and
the nucleus. It is a large protein assembly composed of multiple copies of ~30
nucleoporins (nups).  Structural studies of the NPC have been limited by its considerable
size and complexity. Progress toward understanding the structure of this nanomachine
has benefited from its modular nature, which allows for this 40-60 MDa assembly to be
broken down into subcomplexes that can be studied individually.  While recent work by
both crystallographers and electron microscopists has greatly enhanced our model of the
NPC, the resolution gap between crystal and EM structures remains too large to
confidently place individual proteins within the context of the fully assembled NPC.  In
an effort to arrive at a veritable model of the NPC, we solved the structure of several
scaffold nups and defined the ancestral coatomer element (ACE1) common to a set of
nucleoporins and COPII vesicle coat proteins.  Subsequently, we proposed a lattice-like
model of the NPC, analogous to the COPII lattice, in which ACE1 proteins form the edge
elements and β-propellers form the vertex elements.  Here, we review our recent studies,
speculate on how interactions between subcomplexes of the NPC are mediated, and
outline the steps and challenges that lay ahead on the path to understanding this enormous
assembly in molecular detail.
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