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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

P1 deficiency in myofibers leads to alterations in nuclear parameters. (A) IFM of teased EDL muscle fibers, isolated from wild-type, P1-KO, P1b-KO, MCK-Cre/cKO and desmin KO mice, were subjected to IFM using antibodies to desmin; nuclei were visualized with Hoechst dye. Arrowheads, desmin structures extending from nuclei of wild-type and P1b-KO myofibers. Arrows, desmin-positive structures aggregating in the vicinity of nuclei (P1-KO and MCK-Cre/cKO) as well as throughout the sarcoplasm (MCK-Cre/cKO). Note altered nuclear morphology in P1-KO, MCK-Cre/cKO and desmin-, but not P1b-KO myofibers. Scale bars, 20 µm. (B) Bar graphs representing statistical analyses of nuclear areas, perimeters, shape factors and aspect ratios. Note similarity of alterations observed for P1-KO and MCK-Cre/cKO myofibers. Note also that the perimeter chart x-axis starts at 25 µm. Error bars ± SEM, three experiments, n = 150 nuclei examined in each experiment. *P < 0.05; **P < 0.005; ***P < 0.001. (C) Statistical analysis of distances between nuclei (closest neighbors) determined in specimens as shown in (A). Error bars ± SEM, three experiments, n = 70 total measurements each. *P < 0.05; **P < 0.005; ***P < 0.001. (D) Like (A), using anti-α-actinin instead of anti-desmin antibodies. Note misalignment and disorganization of α-actinin-positive Z-disks in P1−/−, MCK-Cre/cKO and desmin- muscle fibers. Scale bars, 20 µm.
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DDV438F2: P1 deficiency in myofibers leads to alterations in nuclear parameters. (A) IFM of teased EDL muscle fibers, isolated from wild-type, P1-KO, P1b-KO, MCK-Cre/cKO and desmin KO mice, were subjected to IFM using antibodies to desmin; nuclei were visualized with Hoechst dye. Arrowheads, desmin structures extending from nuclei of wild-type and P1b-KO myofibers. Arrows, desmin-positive structures aggregating in the vicinity of nuclei (P1-KO and MCK-Cre/cKO) as well as throughout the sarcoplasm (MCK-Cre/cKO). Note altered nuclear morphology in P1-KO, MCK-Cre/cKO and desmin-, but not P1b-KO myofibers. Scale bars, 20 µm. (B) Bar graphs representing statistical analyses of nuclear areas, perimeters, shape factors and aspect ratios. Note similarity of alterations observed for P1-KO and MCK-Cre/cKO myofibers. Note also that the perimeter chart x-axis starts at 25 µm. Error bars ± SEM, three experiments, n = 150 nuclei examined in each experiment. *P < 0.05; **P < 0.005; ***P < 0.001. (C) Statistical analysis of distances between nuclei (closest neighbors) determined in specimens as shown in (A). Error bars ± SEM, three experiments, n = 70 total measurements each. *P < 0.05; **P < 0.005; ***P < 0.001. (D) Like (A), using anti-α-actinin instead of anti-desmin antibodies. Note misalignment and disorganization of α-actinin-positive Z-disks in P1−/−, MCK-Cre/cKO and desmin- muscle fibers. Scale bars, 20 µm.

Mentions: To investigate the effects of P1 deficiency on perinuclear IF network organization, teased myofibers of wild-type and isoform P1-KO mice were subjected to co-immunostaining using isoform-specific anti-P1 and anti-desmin antibodies. In wild-type cells, P1 showed an accumulation at tail-like appendages associated with the equatorial regions of typically spheroidal and quite flat myonuclei, consistent with previous studies (15,19). Longitudinally extending toward the neighboring nuclei linearly arranged along the myofiber, these structures most probably represented the sarcoplasmic reticulum (Fig. 1A and B, upper rows; and Fig. 2A). The desmin-specific perinuclear staining pattern was very similar to that of P1, except that in this case the nuclear surface seemed to be continuously outlined, whereas this hardly applied for P1. These observations were consistent with the notion that both proteins were associated with the outer nuclear membrane/ER membrane system and that IFs formed cage-like structure around the nucleus.Figure 1.


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)

P1 deficiency in myofibers leads to alterations in nuclear parameters. (A) IFM of teased EDL muscle fibers, isolated from wild-type, P1-KO, P1b-KO, MCK-Cre/cKO and desmin KO mice, were subjected to IFM using antibodies to desmin; nuclei were visualized with Hoechst dye. Arrowheads, desmin structures extending from nuclei of wild-type and P1b-KO myofibers. Arrows, desmin-positive structures aggregating in the vicinity of nuclei (P1-KO and MCK-Cre/cKO) as well as throughout the sarcoplasm (MCK-Cre/cKO). Note altered nuclear morphology in P1-KO, MCK-Cre/cKO and desmin-, but not P1b-KO myofibers. Scale bars, 20 µm. (B) Bar graphs representing statistical analyses of nuclear areas, perimeters, shape factors and aspect ratios. Note similarity of alterations observed for P1-KO and MCK-Cre/cKO myofibers. Note also that the perimeter chart x-axis starts at 25 µm. Error bars ± SEM, three experiments, n = 150 nuclei examined in each experiment. *P < 0.05; **P < 0.005; ***P < 0.001. (C) Statistical analysis of distances between nuclei (closest neighbors) determined in specimens as shown in (A). Error bars ± SEM, three experiments, n = 70 total measurements each. *P < 0.05; **P < 0.005; ***P < 0.001. (D) Like (A), using anti-α-actinin instead of anti-desmin antibodies. Note misalignment and disorganization of α-actinin-positive Z-disks in P1−/−, MCK-Cre/cKO and desmin- muscle fibers. Scale bars, 20 µm.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4664173&req=5

DDV438F2: P1 deficiency in myofibers leads to alterations in nuclear parameters. (A) IFM of teased EDL muscle fibers, isolated from wild-type, P1-KO, P1b-KO, MCK-Cre/cKO and desmin KO mice, were subjected to IFM using antibodies to desmin; nuclei were visualized with Hoechst dye. Arrowheads, desmin structures extending from nuclei of wild-type and P1b-KO myofibers. Arrows, desmin-positive structures aggregating in the vicinity of nuclei (P1-KO and MCK-Cre/cKO) as well as throughout the sarcoplasm (MCK-Cre/cKO). Note altered nuclear morphology in P1-KO, MCK-Cre/cKO and desmin-, but not P1b-KO myofibers. Scale bars, 20 µm. (B) Bar graphs representing statistical analyses of nuclear areas, perimeters, shape factors and aspect ratios. Note similarity of alterations observed for P1-KO and MCK-Cre/cKO myofibers. Note also that the perimeter chart x-axis starts at 25 µm. Error bars ± SEM, three experiments, n = 150 nuclei examined in each experiment. *P < 0.05; **P < 0.005; ***P < 0.001. (C) Statistical analysis of distances between nuclei (closest neighbors) determined in specimens as shown in (A). Error bars ± SEM, three experiments, n = 70 total measurements each. *P < 0.05; **P < 0.005; ***P < 0.001. (D) Like (A), using anti-α-actinin instead of anti-desmin antibodies. Note misalignment and disorganization of α-actinin-positive Z-disks in P1−/−, MCK-Cre/cKO and desmin- muscle fibers. Scale bars, 20 µm.
Mentions: To investigate the effects of P1 deficiency on perinuclear IF network organization, teased myofibers of wild-type and isoform P1-KO mice were subjected to co-immunostaining using isoform-specific anti-P1 and anti-desmin antibodies. In wild-type cells, P1 showed an accumulation at tail-like appendages associated with the equatorial regions of typically spheroidal and quite flat myonuclei, consistent with previous studies (15,19). Longitudinally extending toward the neighboring nuclei linearly arranged along the myofiber, these structures most probably represented the sarcoplasmic reticulum (Fig. 1A and B, upper rows; and Fig. 2A). The desmin-specific perinuclear staining pattern was very similar to that of P1, except that in this case the nuclear surface seemed to be continuously outlined, whereas this hardly applied for P1. These observations were consistent with the notion that both proteins were associated with the outer nuclear membrane/ER membrane system and that IFs formed cage-like structure around the nucleus.Figure 1.

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