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Transmembrane proteins are not required for early stages of nuclear envelope assembly.

ABSTRACT: All identified membrane fusion proteins are transmembrane proteins. In the present study, we explored the post-mitotic reassembly of the NE (nuclear envelope). The proteins that drive membrane rearrangements in NE assembly remain unknown. To determine whether transmembrane proteins are prerequisite components of this fusion machinery, we have focused on nuclear reconstitution in a cell-free system. Mixing of soluble interphase cytosolic extract and MV (membrane vesicles) from amphibian eggs with chromatin results in the formation of functional nuclei. We replaced MV and cytosol with protein-free phosphatidylcholine LS (liposomes) that were pre-incubated with interphase cytosol. While later stages of NE assembly yielding functional nucleus did not proceed without integral proteins of MV, LS-associated cytosolic proteins were sufficient to reconstitute membrane targeting to the chromatin and GTP-dependent lipid mixing. Binding involved LS-associated A-type lamin, and fusion involved Ran GTPase. Thus in contrast with post-fusion stages, fusion initiation in NE assembly, like membrane remodelling in budding and fission, does not require transmembrane proteins.

SUBMITTER: Ramos C

PROVIDER: S-EPMC1698605 | biostudies-other | 2006 Dec

REPOSITORIES: biostudies-other

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Direct membrane protein-DNA interactions required early in nuclear envelope assembly.

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Establishment of tissue-specific genome organisation by muscle-specific nuclear envelope transmembrane proteins (NETs) during mouse C2C12 myoblast differentiation

Project description:This SuperSeries is composed of the SubSeries listed below.

2016-06-17 | GSE80330 | GEO

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