POM121 and Sun1 play a role in early steps of interphase NPC assembly

Talamas, Jessica A.; Hetzer, Martin W.

doi:10.1083/jcb.201012154

Cited by 125 publications

(140 citation statements)

References 35 publications

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“…First, the determined single layer middle position of Pom121 with a radial diameter bigger than that for Nup35 and Nup37 supports the proposal that the transmembrane Nup complex (formed by Pom121, Ndc1 and Gp210) could anchor the NPC into the NE during the early stages of NPC assembly, and then subsequently recruit the inner spoke ring Nup155 complex (containing Nup35) and the outer ring Nup107-160 complex (containing Nup37) to the NPC (Talamas and Hetzer, 2011). Second, the double-layer arrangements of Nup35 and Nup37 agree with the geometry that almost all structural Nups are symmetrically distributed on the cytoplasmic and nuclear sides of NPCs.…”

Section: Discussionsupporting

confidence: 49%

Super-resolution mapping of scaffold nucleoporins in the nuclear pore complex

Kelich

Junod

et al. 2017

Journal of Cell Science

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The nuclear pore complex (NPC), composed of ∼30 different nucleoporins (Nups), is one of the largest supramolecular structures in eukaryotic cells. Its octagonal ring scaffold perforates the nuclear envelope and features a unique molecular machinery that regulates nucleocytoplasmic transport. However, the precise copy number and the spatial location of each Nup in the native NPC remain obscure due to the inherent difficulty of counting and localizing proteins inside of the sub-micrometer supramolecular complex. Here, we combined super-resolution single-point edge-excitation subdiffraction (SPEED) microscopy and nanobody-specific labeling to reveal the spatial distribution of scaffold Nups within three separate layers in the native NPC with a precision of ∼3 nm. Our data reveal both the radial and axial spatial distributions for Pom121, Nup37 and Nup35 and provide evidence for their copy numbers of 8, 32 and 16, respectively, per NPC. This approach can help pave the path for mapping the entirety of Nups in native NPCs and also other structural components of macromolecular complexes.

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Section: Discussionsupporting

confidence: 49%

Super-resolution mapping of scaffold nucleoporins in the nuclear pore complex

Kelich

Junod

et al. 2017

Journal of Cell Science

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“…This structure, therefore, can be thought of as an "ultradonut" with a genus on the order of thousands. How the two membranes assemble in a unique arrangement with such a large number of local fusions is a fundamental question in both physics and biology that is still unresolved (6)(7)(8)(9)(10). To seek an answer to this puzzle, we ask three natural questions based on the common notions in the field of membrane physics.…”

mentioning

confidence: 99%

Ultradonut topology of the nuclear envelope

Torbati

Lele

Agrawal

2016

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

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The nuclear envelope is a unique topological structure formed by lipid membranes in eukaryotic cells. Unlike other membrane structures, the nuclear envelope comprises two concentric membrane shells fused at numerous sites with toroid-shaped pores that impart a "geometric" genus on the order of thousands. Despite the intriguing architecture and vital biological functions of the nuclear membranes, how they achieve and maintain such a unique arrangement remains unknown. Here, we used the theory of elasticity and differential geometry to analyze the equilibrium shape and stability of this structure. Our results show that modest inand out-of-plane stresses present in the membranes not only can define the pore geometry, but also provide a mechanism for destabilizing membranes beyond a critical size and set the stage for the formation of new pores. Our results suggest a mechanism wherein nanoscale buckling instabilities can define the global topology of a nuclear envelope-like structure.nuclear envelope | lipid membranes | topology | buckling instability T he cell nucleus is bounded by two lipid bilayers arranged in a unique geometry called the nuclear envelope. These two bilayers are shaped into concentric spheres that are maintained at a remarkably uniform spacing of ∼ 30−50 nm (1), and yet are fused together at thousands of pores (holes) at an average spacing of ∼ 250−500 nm from each other [based on areal density measurements (2-4)]. At these pores, the membranes locally take on a toroid shape with a radius of curvature on the order of ∼ 20 nm ( Fig. 1). Lipid structures such as vesicles, spherocylinders (bacterial membranes), and biconcave discoids (red blood cell membranes) are all closed structures with no holes, and hence possess a zero genus (5) (Fig. 1). A donut, on the other hand, is also a closed structure but has one hole, and as a result has a genus of 1 (Fig. 1). If we fuse two donuts, we get a shape with a genus of 2, and if we fuse thousands of donuts and bend them to form a sphere, we obtain a nucleus-membrane-like structure ( Fig. 1). This structure, therefore, can be thought of as an "ultradonut" with a genus on the order of thousands. How the two membranes assemble in a unique arrangement with such a large number of local fusions is a fundamental question in both physics and biology that is still unresolved (6-10). To seek an answer to this puzzle, we ask three natural questions based on the common notions in the field of membrane physics.First, can membrane curvature-mediated interactions determine optimal pore number and interpore separation? This principle has been successfully used to predict the interactions of membraneembedded proteins and nanoparticles (11-13). However, in the case of nuclear envelope, Fig. 1C (14) shows that the curved shapes of the membranes at the pores do not persist over interpore length scales; The "curvature memory" of the membranes is lost beyond ∼ 100 nm and they remain essentially flat in between the pores. As a result, a pore does not sense the presence of other p...

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“…A later study has also shown that NPCs colocalize with SUN1, but not with SUN2 (Lu et al, 2008), suggesting that not all SUN proteins colocalize with NPCs. This has since been confirmed when it was reported that SUN1 only associates with NPCs that are formed during interphase, and not with postmitotic NPCs (Talamas and Hetzer, 2011).…”

Section: Introductionmentioning

confidence: 52%

The LINC and NPC relationship – it's complicated!

Jahed

Soheilypour

Peyro

et al. 2016

Journal of Cell Science

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The genetic information of eukaryotic cells is enclosed within a double-layered nuclear envelope, which comprises an inner and outer nuclear membrane. Several transmembrane proteins locate to the nuclear envelope; however, only two integral protein complexes span the nuclear envelope and connect the inside of the nucleus to the cytoplasm. The nuclear pore complex (NPC) acts as a gateway for molecular exchange between the interior of the nucleus and the cytoplasm, whereas so-called LINC complexes physically link the nucleoskeleton and the cytoskeleton. In this Commentary, we will discuss recent studies that have established direct functional associations between these two complexes. The assembly of NPCs and their even distribution throughout the nuclear envelope is dependent on components of the LINC complex. Additionally, LINC complex formation is dependent on the successful localization of inner nuclear membrane components of LINC complexes and their transport through the NPC. Furthermore, the architecture of the nuclear envelope depends on both protein complexes. Finally, we will present recent evidence showing that LINC complexes can affect nucleo-cytoplasmic transport through the NPC, further highlighting the importance of understanding the associations of these essential complexes at the nuclear envelope.

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POM121 and Sun1 play a role in early steps of interphase NPC assembly

Abstract: POM121 and Sun1, but not the Nup107–160 complex, are required for fusion of the inner and outer nuclear membrane during nuclear pore assembly in interphase of the cell cycle.

Cited by 125 publications

References 35 publications

Super-resolution mapping of scaffold nucleoporins in the nuclear pore complex

Super-resolution mapping of scaffold nucleoporins in the nuclear pore complex

Ultradonut topology of the nuclear envelope

The LINC and NPC relationship – it's complicated!

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