PLCγ is enriched on poly-phosphoinositide-rich vesicles to control nuclear envelope assembly

Byrne, Richard; Lhomme, Marie; Han, Kevin; Dowicki, Michael; Nick, Michael; Totty, Nick; Zhendre, Vanessa; Cho, Aeri; Pettitt, Trevor R.; Wakelam, Michael J.O.; Poccia, Dominic; Larijani, Banafshé

doi:10.1016/j.cellsig.2006.10.011

Cited by 40 publications

(61 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The nuclear envelope also contains significant amounts of phosphoinositides and their derivatives (Byrne et al, 2007;Domart et al, 2012;Irvine, 2006;Larijani et al, 2000). Given that the nucleus contains several substrates of Akt, including proteins involved in mRNA processing and DNA damage repair (Blaustein et al, 2005;Boronenkov et al, 1998;Bozulic and Hemmings, 2009;Okada and Ye, 2009), nuclear-localised Akt activation remains an intriguing possibility.…”

Section: Introductionmentioning

confidence: 99%

Endomembrane PtdIns(3,4,5)P3 activates the PI3K/Akt pathway

Jethwa

Chung

Lete

et al. 2015

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

PKB/Akt activation is a common step in tumour growth, proliferation and survival. Akt activation is understood to occur at the plasma membrane of cells in response to growth factor stimulation and local production of the phosphoinositide lipid phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P 3 ] following phosphoinositide 3-kinase (PI3K) activation. The metabolism and turnover of phosphoinositides is complex -they act as signalling molecules as well as structural components of biological membranes. The localisation and significance of internal pools of PtdIns(3,4,5)P 3 has long been speculated upon. By using transfected and recombinant protein probes for PtdIns(3,4,5)P 3 , we show that PtdIns(3,4,5)P 3 is enriched in the nuclear envelope and early endosomes. By exploiting an inducible dimerisation device to recruit Akt to these compartments, we demonstrate that Akt can be locally activated in a PtdIns(3,4,5)P 3 -dependent manner and has the potential to phosphorylate compartmentally localised downstream substrates. This could be an important mechanism to regulate Akt isoform substrate specificity or influence the timing and duration of PI3K pathway signalling. Defects in phosphoinositide metabolism and localisation are known to contribute to cancer, suggesting that interactions at subcellular compartments might be worthwhile targets for therapeutic intervention.

show abstract

Section: Introductionmentioning

confidence: 99%

Endomembrane PtdIns(3,4,5)P3 activates the PI3K/Akt pathway

Jethwa

Chung

Lete

et al. 2015

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…Specific proteins that mediate ER and NE assembly and even relative contributions of proteins present in cytosol, at the membranes, or both in cytosol and at the membranes remain elusive (11,14,15,27). Because MVs fuse and form an ER network in a protein-free buffer supplemented with GTP (28), the proteins required for these rearrangements are either transmembrane proteins or cytosolic proteins tightly associated with the membranes.…”

mentioning

confidence: 99%

Transmembrane Protein-free Membranes Fuse into Xenopus Nuclear Envelope and Promote Assembly of Functional Pores

Rafikova

Melikov

Ramos

et al. 2009

Journal of Biological Chemistry

View full text Add to dashboard Cite

Post-mitotic reassembly of nuclear envelope (NE) and the endoplasmic reticulum (ER) has been reconstituted in a cell-free system based on interphase Xenopus egg extract. To evaluate the relative contributions of cytosolic and transmembrane proteins in NE and ER assembly, we replaced a part of native membrane vesicles with ones either functionally impaired by trypsin or N-ethylmaleimide treatments or with protein-free liposomes. Although neither impaired membrane vesicles nor liposomes formed ER and nuclear membrane, they both supported assembly reactions by fusing with native membrane vesicles. At membrane concentrations insufficient to generate full-sized functional nuclei, addition of liposomes and their fusion with membrane vesicles resulted in an extensive expansion of NE, further chromatin decondensation, restoration of the functionality, and spatial distribution of the nuclear pore complexes (NPCs), and, absent newly delivered transmembrane proteins, an increase in NPC numbers. This rescue of the nuclear assembly by liposomes was inhibited by wheat germ agglutinin and thus required active nuclear transport, similarly to the assembly of full-sized functional NE with membrane vesicles. Mechanism of fusion between liposomes and between liposomes and membrane vesicles was investigated using lipid mixing assay. This fusion required interphase cytosol and, like fusion between native membrane vesicles, was inhibited by guanosine 5-3-O-(thio)triphosphate, soluble N-ethylmaleimide-sensitive factor attachment protein, and N-ethylmaleimide. Our findings suggest that interphase cytosol contains proteins that mediate the fusion stage of ER and NE reassembly, emphasize an unexpected tolerance of nucleus assembly to changes in concentrations of transmembrane proteins, and reveal the existence of a feedback mechanism that couples NE expansion with NPC assembly. The nuclear envelope (NE)2 prevents free diffusion of macromolecules between the nucleus and cytoplasm and therefore separates processes of gene transcription and translation in the cell. In species with an open mitosis, the NE breaks and reassembles during each cell cycle. NE reassembly starts during anaphase and involves formation of a double membrane around segregated chromosomes, insertion of multiprotein nuclear pore complexes (NPCs), and further NE expansion. The outer and inner membranes of NE are connected at the sites of NPCs, which provide selective nucleocytoplasmic transport. The space between nuclear membranes (perinuclear space) is continuous with the endoplasmic reticulum (ER) lumen. The inner nuclear membrane has a specific protein composition and contacts with chromatin and, in metazoans, with lamina.NE formation has been intensively studied in vitro with demembraned chromatin and fractionated Xenopus laevis egg extract (1-5). The fractionation step results in ER disruption and yields membrane-free cytosolic extract along with distinct populations of membrane vesicles (MVs) involved in ER and NE formation (6 -13). It was proposed that NE assembly i...

show abstract

“…To determine the upstream effectors of the fusion machinery [PLC, SFK1 PtdIns(4,5)P 2 and DAG] that are implicated in nuclear envelope formation (Byrne et al, 2007(Byrne et al, , 2009a(Byrne et al, , 2014Poccia and Larijani, 2009), we set out to test the involvement of the class-I PI3Ks and their product PtdIns(3,4,5)P 3 . These experiments were performed initially in cell-free assays and afterwards in situ using intact fertilised sea urchin (Paracentrotus lividus) eggs.…”

Section: Resultsmentioning

confidence: 99%

“…These events are associated in the sea urchin with a subset of membrane vesicles (MV1) that had been isolated from egg cytoplasm that is highly enriched in SFK1, PLCγ and phosphorylated forms of phosphatidylinositol (Byrne et al, 2007(Byrne et al, , 2009b; Collas and Poccia, 1996a). Fusion with MV2 vesicles, which contain an ER marker, depends on and is initiated by the MV1 vesicles in male pronuclei (Collas and Poccia, 1996a;Dumas et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…On the basis of experiments on the in vitro and in vivo formation of the male pronuclear envelope, as well as in vivo data on zygote nuclear envelope formation and karyomere fusion, we have previously presented a common mechanistic model in which fusion is controlled upstream by a Src-family kinase (SFK1) that activates a phosphatidylinositide-specific phospholipase C (PLCγ) that catalyses the hydrolysis of PtdIns(4,5)P 2 , resulting in the production of a fusogenic lipid, diacylglycerol (DAG) (Byrne et al, 2012(Byrne et al, , 2007(Byrne et al, , 2009a(Byrne et al, , 2014Poccia and Larijani, 2009). The in vitro assays have been well documented over many years in several of our publications Poccia, 1996a, 1998;Dumas et al, 2010), and the necessary controls, such as time-resolved Förster resonance energy transfer (FRET) analyses of nuclear envelope membrane fusion and electron micrographs, showing complete formation of the male pronucleus upon the GTP hydrolysis have been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Vesicular PtdIns(3,4,5)P3 and Rab7 are key effectors of sea urchin zygote nuclear membrane fusion

Lete

Byrne

Alonso

et al. 2017

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

Regulation of nuclear envelope dynamics is an important example of the universal phenomena of membrane fusion. The signalling molecules involved in nuclear membrane fusion might also be conserved during the formation of both pronuclear and zygote nuclear envelopes in the fertilised egg. Here, we determine that class-I phosphoinositide 3-kinases (PI3Ks) are needed for in vitro nuclear envelope formation. We show that, in vivo, PtdIns(3,4,5)P 3 is transiently located in vesicles around the male pronucleus at the time of nuclear envelope formation, and around male and female pronuclei before membrane fusion. We illustrate that class-I PI3K activity is also necessary for fusion of the female and male pronuclear membranes. We demonstrate, using coincidence amplified Förster resonance energy transfer (FRET) monitored using fluorescence lifetime imaging microscopy (FLIM), a protein-lipid interaction of Rab7 GTPase and PtdIns(3,4,5)P 3 that occurs during pronuclear membrane fusion to create the zygote nuclear envelope. We present a working model, which includes several molecular steps in the pathways controlling fusion of nuclear envelope membranes.

show abstract

PLCγ is enriched on poly-phosphoinositide-rich vesicles to control nuclear envelope assembly

Cited by 40 publications

References 33 publications

Endomembrane PtdIns(3,4,5)P3 activates the PI3K/Akt pathway

Endomembrane PtdIns(3,4,5)P3 activates the PI3K/Akt pathway

Transmembrane Protein-free Membranes Fuse into Xenopus Nuclear Envelope and Promote Assembly of Functional Pores

Vesicular PtdIns(3,4,5)P3 and Rab7 are key effectors of sea urchin zygote nuclear membrane fusion

Contact Info

Product

Resources

About