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Assemblages: functional units formed by cellular phase separation.

Toretsky JA, Wright PE - J. Cell Biol. (2014)

Bottom Line: The partitioning of intracellular space beyond membrane-bound organelles can be achieved with collections of proteins that are multivalent or contain low-complexity, intrinsically disordered regions.These proteins can undergo a physical phase change to form functional granules or other entities within the cytoplasm or nucleoplasm that collectively we term "assemblage." Intrinsically disordered proteins (IDPs) play an important role in forming a subset of cellular assemblages by promoting phase separation.Recent work points to an involvement of assemblages in disease states, indicating that intrinsic disorder and phase transitions should be considered in the development of therapeutics.

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Affiliation: Department of Oncology, Georgetown University, Washington, DC 20057 jat42@georgetown.edu.

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Phase transition caused by IDPs regulates transport in nuclear pore channels. (A) Sagittal plane of a nuclear pore that is populated with IDPs. FG proteins, and variants described in the text, contribute to the “filling” of space between structural protein components (gray). The architecture of the NPC creates zones of transport, indicated here as light red and light blue. (B) Transverse view of nuclear pore complex components (Nups) showing the localization of FG proteins and the transport zones. (C) Legend demonstrating the types of proteins found in the nuclear pore complex and their biophysical characteristics. This figure is based upon Saccharomyces cerevisiae FG Nups and is adapted from Yamada et al. (2010).
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fig2: Phase transition caused by IDPs regulates transport in nuclear pore channels. (A) Sagittal plane of a nuclear pore that is populated with IDPs. FG proteins, and variants described in the text, contribute to the “filling” of space between structural protein components (gray). The architecture of the NPC creates zones of transport, indicated here as light red and light blue. (B) Transverse view of nuclear pore complex components (Nups) showing the localization of FG proteins and the transport zones. (C) Legend demonstrating the types of proteins found in the nuclear pore complex and their biophysical characteristics. This figure is based upon Saccharomyces cerevisiae FG Nups and is adapted from Yamada et al. (2010).

Mentions: Although FG repeats are a broad class of Nup, sequence variations such as FxFG and FLFG, along with FG, are differentially distributed at the cytoplasmic, intra-NPC, or nucleoplasmic regions of the NPC (Atkinson et al., 2013). A mutagenesis analysis of the role of FG repeat Nups in yeast suggests that multiple pathways exist for transport through the nuclear pore (Strawn et al., 2004). The FG Nups are structurally heterogeneous, adopting a spectrum of disordered conformational states that range from collapsed coils to highly extended configurations (Yamada et al., 2010), leading to a zonal model of the nuclear pore (Fig. 2). Additional investigations support a critical role for FG nucleoporins in the transport of mRNA, including relative specificities for GLFG and FxFG repeat sequences (Terry and Wente, 2007).


Assemblages: functional units formed by cellular phase separation.

Toretsky JA, Wright PE - J. Cell Biol. (2014)

Phase transition caused by IDPs regulates transport in nuclear pore channels. (A) Sagittal plane of a nuclear pore that is populated with IDPs. FG proteins, and variants described in the text, contribute to the “filling” of space between structural protein components (gray). The architecture of the NPC creates zones of transport, indicated here as light red and light blue. (B) Transverse view of nuclear pore complex components (Nups) showing the localization of FG proteins and the transport zones. (C) Legend demonstrating the types of proteins found in the nuclear pore complex and their biophysical characteristics. This figure is based upon Saccharomyces cerevisiae FG Nups and is adapted from Yamada et al. (2010).
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4151146&req=5

fig2: Phase transition caused by IDPs regulates transport in nuclear pore channels. (A) Sagittal plane of a nuclear pore that is populated with IDPs. FG proteins, and variants described in the text, contribute to the “filling” of space between structural protein components (gray). The architecture of the NPC creates zones of transport, indicated here as light red and light blue. (B) Transverse view of nuclear pore complex components (Nups) showing the localization of FG proteins and the transport zones. (C) Legend demonstrating the types of proteins found in the nuclear pore complex and their biophysical characteristics. This figure is based upon Saccharomyces cerevisiae FG Nups and is adapted from Yamada et al. (2010).
Mentions: Although FG repeats are a broad class of Nup, sequence variations such as FxFG and FLFG, along with FG, are differentially distributed at the cytoplasmic, intra-NPC, or nucleoplasmic regions of the NPC (Atkinson et al., 2013). A mutagenesis analysis of the role of FG repeat Nups in yeast suggests that multiple pathways exist for transport through the nuclear pore (Strawn et al., 2004). The FG Nups are structurally heterogeneous, adopting a spectrum of disordered conformational states that range from collapsed coils to highly extended configurations (Yamada et al., 2010), leading to a zonal model of the nuclear pore (Fig. 2). Additional investigations support a critical role for FG nucleoporins in the transport of mRNA, including relative specificities for GLFG and FxFG repeat sequences (Terry and Wente, 2007).

Bottom Line: The partitioning of intracellular space beyond membrane-bound organelles can be achieved with collections of proteins that are multivalent or contain low-complexity, intrinsically disordered regions.These proteins can undergo a physical phase change to form functional granules or other entities within the cytoplasm or nucleoplasm that collectively we term "assemblage." Intrinsically disordered proteins (IDPs) play an important role in forming a subset of cellular assemblages by promoting phase separation.Recent work points to an involvement of assemblages in disease states, indicating that intrinsic disorder and phase transitions should be considered in the development of therapeutics.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Oncology, Georgetown University, Washington, DC 20057 jat42@georgetown.edu.

Show MeSH
Related in: MedlinePlus