NEP-A and NEP-B both contribute to nuclear pore formation in Xenopus eggs and oocytes

Salpingidou, Georgia; Rzepecki, Ryszard; Киселева, Елена; Lyon, Carol E.; Lane, B.; Fusiek, Kasia; Golebiewska, Anna; Drummond, Sheona P; Allen, Terence D; Ellis, Juliet A.; Smythe, Carl; Goldberg, Martin W.; Hutchison, Christopher J.

doi:10.1242/jcs.019968

Cited by 14 publications

(26 citation statements)

References 50 publications

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“…Egg collection and extract preparation were according to Salpingidou et al [69]. For sperm chromatin isolation male frogs were pre-stimulated with two portions of 150 iU of HCG (Human Chorionic Gonadotropin; Sigma) 48 and 24 hours before sperm isolation.…”

Section: Methodsmentioning

confidence: 99%

The Different Function of Single Phosphorylation Sites of Drosophila melanogaster Lamin Dm and Lamin C

Zaremba-Czogalla¹,

Piekarowicz²,

Wachowicz³

et al. 2012

PLoS ONE

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Lamins' functions are regulated by phosphorylation at specific sites but our understanding of the role of such modifications is practically limited to the function of cdc 2 (cdk1) kinase sites in depolymerization of the nuclear lamina during mitosis. In our study we used Drosophila lamin Dm (B-type) to examine the function of particular phosphorylation sites using pseudophosphorylated mutants mimicking single phosphorylation at experimentally confirmed in vivo phosphosites (S25E, S45E, T435E, S595E). We also analyzed lamin C (A-type) and its mutant S37E representing the N-terminal cdc2 (mitotic) site as well as lamin Dm R64H mutant as a control, non-polymerizing lamin. In the polymerization assay we could observe different effects of N-terminal cdc2 site pseudophosphorylation on A- and B-type lamins: lamin Dm S45E mutant was insoluble, in contrast to lamin C S37E. Lamin Dm T435E (C-terminal cdc2 site) and R64H were soluble in vitro. We also confirmed that none of the single phosphorylation site modifications affected the chromatin binding of lamin Dm, in contrast to the lamin C N-terminal cdc2 site. In vivo, all lamin Dm mutants were incorporated efficiently into the nuclear lamina in transfected Drosophila S2 and HeLa cells, although significant amounts of S45E and T435E were also located in cytoplasm. When farnesylation incompetent mutants were expressed in HeLa cells, lamin Dm T435E was cytoplasmic and showed higher mobility in FRAP assay.

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Section: Methodsmentioning

confidence: 99%

The Different Function of Single Phosphorylation Sites of Drosophila melanogaster Lamin Dm and Lamin C

Zaremba-Czogalla¹,

Piekarowicz²,

Wachowicz³

et al. 2012

PLoS ONE

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Section: The Interphase Nucleusmentioning

confidence: 99%

“…In growing Xenopus oocyte nuclei the presence of vesicles on the ONM has been interpreted as evidence for vesicle fusion. However, an alternative explanation is that these vesicles were generated during EM sample preparation by rupturing of ER tubules [71].Growth of the INM requires passage of membrane components through the fusion sites with the ONM at the NPCs. The current view is that INM proteins are retained once they reach the INM by interactions with either the lamina or chromatin.…”

mentioning

confidence: 99%

The life cycle of the metazoan nuclear envelope

Anderson

Hetzer

2008

Current Opinion in Cell Biology

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The nuclear envelope is a double-layered membrane that encloses the nuclear genome and transcriptional machinery. In dividing cells of metazoa, the nucleus completely disassembles during mitosis creating the need to re-establish the nuclear compartment at the end of each cell division. Given the crucial role of the nuclear envelope in gene regulation and cellular organization, it is not surprising that its biogenesis and organization have become active research areas. We will review recent insights into nuclear membrane dynamics during the cell cycle. IntroductionA physical membrane barrier around the nucleus was first suspected almost 100 years ago based on micromanipulation studies [1]. Later, electron microscopy (EM) images revealed that these 'nuclear envelopes' consist of two parallel membranes, the inner (INM) and outer nuclear membrane (ONM) [2]. Both membranes are penetrated by nuclear pore complexes (NPCs), large protein assemblies that mediate bidirectional exchange of molecules between the nucleoplasm and the cytoplasm [3]. The ONM is continuous with the endoplasmic reticulum (ER) and is studded with ribosomes. Although lipids can diffuse freely between the NE and the ER (Figure 1, Interphase), the protein composition of the NE differs dramatically from ER tubules and sheets. This indicates specific mechanisms of protein targeting and unique roles of the NE in regulating nuclear functions. Research of the last few years has revealed active roles of the NE in the organization of chromatin and the cytoskeleton as well as in cell cycle progression [4]. For instance, recent studies have demonstrated that heterochromatin tightly associates with the INM and the targeting of certain chromatin regions to the NE directly controls gene expression [5][6][7]. NE proteins, which mediate the multiple NE functions, can be categorized in essentially four classes: components of the nuclear pore, INM-and ONM-proteins and lamins. The first group is composed of ∼30 proteins, nucleoporins, which constitute the NPCs, the exclusive sites of nucleocytoplasmic transport [3]. NPCs form hollow cylinders with nucleoplasmic and cytoplasmic filamentous attachments that together form a transport channel across the lipid bilayer [8]. Although NPCs are membrane embedded, only three transmembrane nucleoporins have been identified, leaving us with the puzzle of how this ∼90 MDa complex assembles. A detailed model of the molecular architecture of the yeast NPC was recently proposed based on biophysical and proteomic parameters [9], and is likely to provide important insights into the pore structure in metazoa since the overall shape and protein folds seem to have been conserved throughout evolution. The second group of proteins, which specifically localizes to the INM [10], links the NE to chromatin organization. For instance, several integral membrane proteins such as emerin, lamin B receptor, Lap 2β and MAN1 have been shown to interact with regulators of chromatin organization (e.g. HP1 and BAF) and transcription factors [11,12] The ...

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“…Thus it is likely that vesicle fusion functions only during the NE reassembly step in intact cells. Various studies indicate that, in addition to p97, this step requires certain NPC proteins, including the integral NPC protein gp210 (glycoprotein 210) and the GTPase Ran [34][35][36][37].…”

Section: Vesicle Fusion In the Nementioning

confidence: 99%

Inner nuclear membrane protein transport is mediated by multiple mechanisms

Zuleger

Korfali

Schirmer

2008

Biochemical Society Transactions

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Work in the nuclear transport field has led to an incredibly detailed description of protein translocation through the central channel of the nuclear pore complex, yet the mechanism by which nuclear envelope transmembrane proteins reach the inner nuclear membrane after synthesis in the endoplasmic reticulum is still hotly debated. Three different translocation models have gained experimental support: (i) simple lateral diffusion through the nuclear envelope membrane system; (ii) translocation by vesicle fusion events; and (iii) a variation on classical transport mediated by the nuclear pore complex. Although these models appear to be mutually exclusive, in the present paper we argue that they probably all function for different inner nuclear membrane proteins according to their unique characteristics.

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NEP-A and NEP-B both contribute to nuclear pore formation in Xenopus eggs and oocytes

Cited by 14 publications

References 50 publications

The Different Function of Single Phosphorylation Sites of Drosophila melanogaster Lamin Dm and Lamin C

The Different Function of Single Phosphorylation Sites of Drosophila melanogaster Lamin Dm and Lamin C

The life cycle of the metazoan nuclear envelope

Inner nuclear membrane protein transport is mediated by multiple mechanisms

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