Systematic analysis of barrier-forming FG hydrogels from Xenopus nuclear pore complexes

Labokha, Aksana A.; Gradmann, Sabine; Frey, Steffen; Hülsmann, Bastian B.; Urlaub, Henning; Baldus, Marc; Görlich, Dirk

doi:10.1038/emboj.2012.302

Cited by 182 publications

(278 citation statements)

References 81 publications

(126 reference statements)

Supporting

Mentioning

246

Contrasting

Order By: Relevance

“…Our simulations describe important microscopic aspects of the FG-TF interaction at an atomic-level resolution, aspects that are not explicitly considered by any of the previously proposed mesoscale models of nucleocytoplasmic transport (1,3,15,(23)(24)(25)(26)(27)(28)72). Nonetheless, it is informative to assess our results in the context of those models.…”

Section: Discussionmentioning

confidence: 97%

Slide-and-exchange mechanism for rapid and selective transport through the nuclear pore complex

Raveh

Karp

Sparks

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

131

View full text Add to dashboard Cite

Nucleocytoplasmic transport is mediated by the interaction of transport factors (TFs) with disordered phenylalanine-glycine (FG) repeats that fill the central channel of the nuclear pore complex (NPC). However, the mechanism by which TFs rapidly diffuse through multiple FG repeats without compromising NPC selectivity is not yet fully understood. In this study, we build on our recent NMR investigations showing that FG repeats are highly dynamic, flexible, and rapidly exchanging among TF interaction sites. We use unbiased long timescale all-atom simulations on the Anton supercomputer, combined with extensive enhanced sampling simulations and NMR experiments, to characterize the thermodynamic and kinetic properties of FG repeats and their interaction with a model transport factor. Both the simulations and experimental data indicate that FG repeats are highly dynamic random coils, lack intrachain interactions, and exhibit significant entropically driven resistance to spatial confinement. We show that the FG motifs reversibly slide in and out of multiple TF interaction sites, transitioning rapidly between a strongly interacting state and a weakly interacting state, rather than undergoing a much slower transition between strongly interacting and completely noninteracting (unbound) states. In the weakly interacting state, FG motifs can be more easily displaced by other competing FG motifs, providing a simple mechanism for rapid exchange of TF/FG motif contacts during transport. This slide-and-exchange mechanism highlights the direct role of the disorder within FG repeats in nucleocytoplasmic transport, and resolves the apparent conflict between the selectivity and speed of transport.nuclear pore | molecular dynamics | nucleoporins | transport factors | NMR T he nuclear pore complex (NPC) regulates macromolecular transport between the nucleus and the cytoplasm in all eukaryotic cells (1, 2). The NPC allows for passive diffusion of small molecules including sugars, ions, and water, while simultaneously imposing size-dependent exclusion of macromolecules without nuclear transport factor (TF) binding sites, generating unique nuclear and cytoplasmic compartments (3, 4). Larger macromolecules can bypass the selectivity barrier of the NPC by interacting with TFs that shuttle cargo through the central channel of the pore. In pathological conditions, including many cancers and viral infections, the NPC is hijacked and used to transport undesired particles, or it is modified to attenuate the cellular responses to disease onset (5, 6).TFs traverse the NPC by selective and reversible association with disordered phenylalanine-glycine (FG) repeat domains of the FG nucleoporin proteins (FG Nups), which line the surface of the NPC (7-14). Each FG repeat domain consists of 5-50 FG repeats. In turn, each FG repeat consists of a single FG motif of various sequence flavors, such as the FSFG and GLFG motifs, and 10-30 spacer residues that separate consecutive FG motifs (15, 16). The spacer residues are strongly hydrophilic (17) and rich ...

show abstract

Section: Discussionmentioning

confidence: 97%

Slide-and-exchange mechanism for rapid and selective transport through the nuclear pore complex

Raveh

Karp

Sparks

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

131

View full text Add to dashboard Cite

show abstract

“…2), the O-GlcNAc modification likely holds functional importance. Indeed, recent studies showed that O-GlcNAc glycosylation of nuclear pore proteins prevents their proteasomal degradation (85) and facilitates the transport of protein cargo (86). Interestingly, phosphorylation of nuclear pore proteins, including NUP214, also increases after T cell activation (83), which raises the possibility of multiple posttranslational modifications working synergistically to regulate nuclear pore function in activated T cells.…”

Section: Discussionmentioning

confidence: 99%

Global Analysis of O-GlcNAc Glycoproteins in Activated Human T Cells

Lund

Elias

Davis

2016

The Journal of Immunology

View full text Add to dashboard Cite

T cell activation in response to Ag is largely regulated by protein posttranslational modifications. Although phosphorylation has been extensively characterized in T cells, much less is known about the glycosylation of serine/threonine residues by O-linked N-acetylglucosamine (O-GlcNAc). Given that O-GlcNAc appears to regulate cell signaling pathways and protein activity similarly to phosphorylation, we performed a comprehensive analysis of O-GlcNAc during T cell activation to address the functional importance of this modification and to identify the modified proteins. Activation of T cells through the TCR resulted in a global elevation of O-GlcNAc levels and in the absence of O-GlcNAc, IL-2 production and proliferation were compromised. T cell activation also led to changes in the relative expression of O-GlcNAc transferase (OGT) isoforms and accumulation of OGT at the immunological synapse of murine T cells. Using a glycoproteomics approach, we identified >200 O-GlcNAc proteins in human T cells. Many of the identified proteins had a functional relationship to RNA metabolism, and consistent with a connection between O-GlcNAc and RNA, inhibition of OGT impaired nascent RNA synthesis upon T cell activation. Overall, our studies provide a global analysis of O-GlcNAc dynamics during T cell activation and the first characterization, to our knowledge, of the O-GlcNAc glycoproteome in human T cells.

show abstract

“…Recent work has provided strong evidence for the socalled 'selective-phase model ' (Hülsmann et al, 2012;Labokha et al, 2013). In this model, FG-Nups line the central channel and extend their FG-repeat regions into the middle of the channel.…”

Section: The Fg Barriermentioning

confidence: 99%

The nuclear pore complex – structure and function at a glance

Kabachinski

Schwartz

2015

Journal of Cell Science

171

135

View full text Add to dashboard Cite

Nuclear pore complexes (NPCs) are indispensable for cell function and are at the center of several human diseases. NPCs provide access to the nucleus and regulate the transport of proteins and RNA across the nuclear envelope. They are aqueous channels generated from a complex network of evolutionarily conserved proteins known as nucleporins. In this Cell Science at a Glance article and the accompanying poster, we discuss how transport between the nucleoplasm and the cytoplasm is regulated, what we currently know about the structure of individual nucleoporins and the assembled NPC, and how the cell regulates assembly and disassembly of such a massive structure. Our aim is to provide a general overview on what we currently know about the nuclear pore and point out directions of research this area is heading to.

show abstract

Systematic analysis of barrier-forming FG hydrogels from Xenopus nuclear pore complexes

Cited by 182 publications

References 81 publications

Slide-and-exchange mechanism for rapid and selective transport through the nuclear pore complex

Slide-and-exchange mechanism for rapid and selective transport through the nuclear pore complex

Global Analysis of O-GlcNAc Glycoproteins in Activated Human T Cells

The nuclear pore complex – structure and function at a glance

Contact Info

Product

Resources

About