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Plectin isoform 1-dependent nuclear docking of desmin networks affects myonuclear architecture and expression of mechanotransducers.

Staszewska I, Fischer I, Wiche G - Hum. Mol. Genet. (2015)

Bottom Line: We show that P1-mediated targeting of desmin IFs to myonuclei is essential for maintenance of their typically spheroidal architecture as well as their proper positioning and movement along the myofiber.Mechanistically, P1 is shown to specifically interact with the myonuclear membrane-associated (BAR domain-containing) protein endophilin B.Our results open a new perspective on cytoskeleton-nuclear crosstalk via specific cytolinker proteins.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria.

No MeSH data available.


Related in: MedlinePlus

Endophilin B2 colocalizes and interacts with P1 at the periphery of myofibers. (A) Teased EDL muscle fibers derived from wild-type and P1-KO mice were immunolabeled using antibodies to desmin and either endoB1 (upper panels) or endoB2 (lower panels). Note colocalization of both endophilins with desmin-positive tail-like structures at the nuclear periphery in wild-type fibers, in contrast to the diffuse distribution of endophilins in the vicinity of P1-KO myonuclei. Scale bars, 10 µm. (B) SDS-PAGE (Coomassie-staining) of recombinant proteins (GST-tagged endoB1 and endoB2, and GST protein) used in pull-down assays. (C) Myotubes differentiated from wild-type and P1–/– myoblasts were subjected to GST pull-down assays; GST protein served as negative control. Proteins pulled-down and total cell lysates (input) were analyzed by IB and probed with either anti-pan plectin or anti-GST antibodies using two separate (6 and 10% polyacrylamide) gels. Note positive plectin signals in GST-endoB1 as well as GST-endoB2 pull-down samples from wild-type lysates. *, empty lane.
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DDV438F8: Endophilin B2 colocalizes and interacts with P1 at the periphery of myofibers. (A) Teased EDL muscle fibers derived from wild-type and P1-KO mice were immunolabeled using antibodies to desmin and either endoB1 (upper panels) or endoB2 (lower panels). Note colocalization of both endophilins with desmin-positive tail-like structures at the nuclear periphery in wild-type fibers, in contrast to the diffuse distribution of endophilins in the vicinity of P1-KO myonuclei. Scale bars, 10 µm. (B) SDS-PAGE (Coomassie-staining) of recombinant proteins (GST-tagged endoB1 and endoB2, and GST protein) used in pull-down assays. (C) Myotubes differentiated from wild-type and P1–/– myoblasts were subjected to GST pull-down assays; GST protein served as negative control. Proteins pulled-down and total cell lysates (input) were analyzed by IB and probed with either anti-pan plectin or anti-GST antibodies using two separate (6 and 10% polyacrylamide) gels. Note positive plectin signals in GST-endoB1 as well as GST-endoB2 pull-down samples from wild-type lysates. *, empty lane.

Mentions: Recently, it has been shown that endophilin B2 (endoB2), a BAR domain-containing protein, binds specifically to P1 in HeLa cells (37). Because proteins with BAR domains are essential in controlling the shape and dynamics of intracellular membranes, we assessed whether this type of interaction occurs in myofibers. Analyzing the localization of endophilins in teased wild-type myofibers by IFM, using antibodies to endophilin B1 (endoB1) and endoB2 as well as desmin, we observed colocalization of both endophilins with desmin in characteristic tail-like structures at the nuclear periphery and partially also at Z-disks, whereby the signal for endoB2 at the nuclear edges was much stronger than that of endoB1 (Fig. 8A, upper panels). Intriguingly, in P1-deficient myofibers, neither one of these endophilins was found accumulated at the nuclear periphery any more. Their staining patterns were rather diffuse in perinuclear regions and more restricted to Z-disks, contrasting the perinuclear accumulation of desmin-positive aggregates (Fig. 8A, lower panels). These observations supported the notion that P1 indeed is an interaction partner of endophilins at the nuclear membrane of myofibers.Figure 8.


Plectin isoform 1-dependent nuclear docking of desmin networks affects myonuclear architecture and expression of mechanotransducers.

Staszewska I, Fischer I, Wiche G - Hum. Mol. Genet. (2015)

Endophilin B2 colocalizes and interacts with P1 at the periphery of myofibers. (A) Teased EDL muscle fibers derived from wild-type and P1-KO mice were immunolabeled using antibodies to desmin and either endoB1 (upper panels) or endoB2 (lower panels). Note colocalization of both endophilins with desmin-positive tail-like structures at the nuclear periphery in wild-type fibers, in contrast to the diffuse distribution of endophilins in the vicinity of P1-KO myonuclei. Scale bars, 10 µm. (B) SDS-PAGE (Coomassie-staining) of recombinant proteins (GST-tagged endoB1 and endoB2, and GST protein) used in pull-down assays. (C) Myotubes differentiated from wild-type and P1–/– myoblasts were subjected to GST pull-down assays; GST protein served as negative control. Proteins pulled-down and total cell lysates (input) were analyzed by IB and probed with either anti-pan plectin or anti-GST antibodies using two separate (6 and 10% polyacrylamide) gels. Note positive plectin signals in GST-endoB1 as well as GST-endoB2 pull-down samples from wild-type lysates. *, empty lane.
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Related In: Results  -  Collection

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DDV438F8: Endophilin B2 colocalizes and interacts with P1 at the periphery of myofibers. (A) Teased EDL muscle fibers derived from wild-type and P1-KO mice were immunolabeled using antibodies to desmin and either endoB1 (upper panels) or endoB2 (lower panels). Note colocalization of both endophilins with desmin-positive tail-like structures at the nuclear periphery in wild-type fibers, in contrast to the diffuse distribution of endophilins in the vicinity of P1-KO myonuclei. Scale bars, 10 µm. (B) SDS-PAGE (Coomassie-staining) of recombinant proteins (GST-tagged endoB1 and endoB2, and GST protein) used in pull-down assays. (C) Myotubes differentiated from wild-type and P1–/– myoblasts were subjected to GST pull-down assays; GST protein served as negative control. Proteins pulled-down and total cell lysates (input) were analyzed by IB and probed with either anti-pan plectin or anti-GST antibodies using two separate (6 and 10% polyacrylamide) gels. Note positive plectin signals in GST-endoB1 as well as GST-endoB2 pull-down samples from wild-type lysates. *, empty lane.
Mentions: Recently, it has been shown that endophilin B2 (endoB2), a BAR domain-containing protein, binds specifically to P1 in HeLa cells (37). Because proteins with BAR domains are essential in controlling the shape and dynamics of intracellular membranes, we assessed whether this type of interaction occurs in myofibers. Analyzing the localization of endophilins in teased wild-type myofibers by IFM, using antibodies to endophilin B1 (endoB1) and endoB2 as well as desmin, we observed colocalization of both endophilins with desmin in characteristic tail-like structures at the nuclear periphery and partially also at Z-disks, whereby the signal for endoB2 at the nuclear edges was much stronger than that of endoB1 (Fig. 8A, upper panels). Intriguingly, in P1-deficient myofibers, neither one of these endophilins was found accumulated at the nuclear periphery any more. Their staining patterns were rather diffuse in perinuclear regions and more restricted to Z-disks, contrasting the perinuclear accumulation of desmin-positive aggregates (Fig. 8A, lower panels). These observations supported the notion that P1 indeed is an interaction partner of endophilins at the nuclear membrane of myofibers.Figure 8.

Bottom Line: We show that P1-mediated targeting of desmin IFs to myonuclei is essential for maintenance of their typically spheroidal architecture as well as their proper positioning and movement along the myofiber.Mechanistically, P1 is shown to specifically interact with the myonuclear membrane-associated (BAR domain-containing) protein endophilin B.Our results open a new perspective on cytoskeleton-nuclear crosstalk via specific cytolinker proteins.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria.

No MeSH data available.


Related in: MedlinePlus