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A genetic screen identifies Tor as an interactor of VAPB in a Drosophila model of amyotrophic lateral sclerosis.

Deivasigamani S, Verma HK, Ueda R, Ratnaparkhi A, Ratnaparkhi GS - Biol Open (2014)

Bottom Line: One key modifier identified was Tor, whose knockdown reversed the large bouton phenotype associated with VAP(P58S) expression in neurons.A similar reversal was seen by over-expressing Tuberous Sclerosis Complex (Tsc1,2) that negatively regulates TOR signaling as also by reduction of S6K activity.In comparison, the small bouton phenotype associated with VAP(wt) expression was reversed with Tsc1 knock down as well as S6K-CA expression.

View Article: PubMed Central - PubMed

Affiliation: Indian Institute of Science Education and Research, Pune 411021, India.

No MeSH data available.


Related in: MedlinePlus

Decreased TSC activity and increased S6K activity reverses the VAP(wt) small bouton phenotype.(A) VAP wild type over-expression using C155-Gal4 leads to reduced bouton size. (B–D) Reducing TOR pathway activity by over-expressing Tsc1,2 (B) or TOR dominant negative (D) does not affect the bouton size in the VAP wild type over-expression background. However, increasing TOR pathway activity using Tsc1 knock down increased the bouton size to wild types levels (C). (E–H) TOR downstream components can alter the bouton size in VAP wild type over-expression. Over-expression of a constitutively active form of S6K (E) and constitutively active Thor (G) rescues the bouton size, while the dominant negative form does not (F). Over-expression of Atg1 along VAP wild type reduced the bouton size further (H). Scale bar: 5 µm. Average size of boutons from about 15 NMJs is displayed in yellow at the top right of each figure. (I) Quantitation of effect of TOR pathway and its downstream components in VAP wild type over-expression mediated bouton size. Error bars represent SEM. * indicates a p-value<0.01 (but >0.001), while ** indicates a p-value of <0.001.
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f07: Decreased TSC activity and increased S6K activity reverses the VAP(wt) small bouton phenotype.(A) VAP wild type over-expression using C155-Gal4 leads to reduced bouton size. (B–D) Reducing TOR pathway activity by over-expressing Tsc1,2 (B) or TOR dominant negative (D) does not affect the bouton size in the VAP wild type over-expression background. However, increasing TOR pathway activity using Tsc1 knock down increased the bouton size to wild types levels (C). (E–H) TOR downstream components can alter the bouton size in VAP wild type over-expression. Over-expression of a constitutively active form of S6K (E) and constitutively active Thor (G) rescues the bouton size, while the dominant negative form does not (F). Over-expression of Atg1 along VAP wild type reduced the bouton size further (H). Scale bar: 5 µm. Average size of boutons from about 15 NMJs is displayed in yellow at the top right of each figure. (I) Quantitation of effect of TOR pathway and its downstream components in VAP wild type over-expression mediated bouton size. Error bars represent SEM. * indicates a p-value<0.01 (but >0.001), while ** indicates a p-value of <0.001.

Mentions: In a VAP(wt) background co-expressing Tsc1,2 in did not rescue the small bouton phenotype (Fig. 7A,B,I). But down-regulation of Tsc1 rescued the phenotype dramatically (3.39±0.13 vs 4.75±0.16, p-value<0.0001, Fig. 7A,C,I) suggesting lowered TOR signaling when VAP(wt) is expressed in neurons. TOR-TED, when expressed, did not modify the small bouton size (3.69±0.08 µm vs 3.39±0.13 µm, p-value = 0.055; Fig. 7A,D,I). Thor CA, when expressed in a VAP(wt) background, rescues the small bouton phenotype (3.39±0.12 vs 4.41±0.15 µm, p-value = 0.0002, Fig. 7G,I); but Thor CA by itself lead to larger boutons (supplementary material Fig. S3E). Co-expresssion of Atg1 with VAP(wt) leads to smaller boutons, a phenotype negated by the fact that Atg1 over-expression by itself leads to small boutons. S6K-DN in a VAP(wt) expression background does not change the small bouton phenotype but S6K-CA expression rescues the phenotype (3.39±0.12 µm vs 4.15±0.13 µm, p-value = 0.0003, Fig. 7E,I). This suggests that TOR signaling may be down regulated in neurons over-expressing VAP(wt).


A genetic screen identifies Tor as an interactor of VAPB in a Drosophila model of amyotrophic lateral sclerosis.

Deivasigamani S, Verma HK, Ueda R, Ratnaparkhi A, Ratnaparkhi GS - Biol Open (2014)

Decreased TSC activity and increased S6K activity reverses the VAP(wt) small bouton phenotype.(A) VAP wild type over-expression using C155-Gal4 leads to reduced bouton size. (B–D) Reducing TOR pathway activity by over-expressing Tsc1,2 (B) or TOR dominant negative (D) does not affect the bouton size in the VAP wild type over-expression background. However, increasing TOR pathway activity using Tsc1 knock down increased the bouton size to wild types levels (C). (E–H) TOR downstream components can alter the bouton size in VAP wild type over-expression. Over-expression of a constitutively active form of S6K (E) and constitutively active Thor (G) rescues the bouton size, while the dominant negative form does not (F). Over-expression of Atg1 along VAP wild type reduced the bouton size further (H). Scale bar: 5 µm. Average size of boutons from about 15 NMJs is displayed in yellow at the top right of each figure. (I) Quantitation of effect of TOR pathway and its downstream components in VAP wild type over-expression mediated bouton size. Error bars represent SEM. * indicates a p-value<0.01 (but >0.001), while ** indicates a p-value of <0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4232771&req=5

f07: Decreased TSC activity and increased S6K activity reverses the VAP(wt) small bouton phenotype.(A) VAP wild type over-expression using C155-Gal4 leads to reduced bouton size. (B–D) Reducing TOR pathway activity by over-expressing Tsc1,2 (B) or TOR dominant negative (D) does not affect the bouton size in the VAP wild type over-expression background. However, increasing TOR pathway activity using Tsc1 knock down increased the bouton size to wild types levels (C). (E–H) TOR downstream components can alter the bouton size in VAP wild type over-expression. Over-expression of a constitutively active form of S6K (E) and constitutively active Thor (G) rescues the bouton size, while the dominant negative form does not (F). Over-expression of Atg1 along VAP wild type reduced the bouton size further (H). Scale bar: 5 µm. Average size of boutons from about 15 NMJs is displayed in yellow at the top right of each figure. (I) Quantitation of effect of TOR pathway and its downstream components in VAP wild type over-expression mediated bouton size. Error bars represent SEM. * indicates a p-value<0.01 (but >0.001), while ** indicates a p-value of <0.001.
Mentions: In a VAP(wt) background co-expressing Tsc1,2 in did not rescue the small bouton phenotype (Fig. 7A,B,I). But down-regulation of Tsc1 rescued the phenotype dramatically (3.39±0.13 vs 4.75±0.16, p-value<0.0001, Fig. 7A,C,I) suggesting lowered TOR signaling when VAP(wt) is expressed in neurons. TOR-TED, when expressed, did not modify the small bouton size (3.69±0.08 µm vs 3.39±0.13 µm, p-value = 0.055; Fig. 7A,D,I). Thor CA, when expressed in a VAP(wt) background, rescues the small bouton phenotype (3.39±0.12 vs 4.41±0.15 µm, p-value = 0.0002, Fig. 7G,I); but Thor CA by itself lead to larger boutons (supplementary material Fig. S3E). Co-expresssion of Atg1 with VAP(wt) leads to smaller boutons, a phenotype negated by the fact that Atg1 over-expression by itself leads to small boutons. S6K-DN in a VAP(wt) expression background does not change the small bouton phenotype but S6K-CA expression rescues the phenotype (3.39±0.12 µm vs 4.15±0.13 µm, p-value = 0.0003, Fig. 7E,I). This suggests that TOR signaling may be down regulated in neurons over-expressing VAP(wt).

Bottom Line: One key modifier identified was Tor, whose knockdown reversed the large bouton phenotype associated with VAP(P58S) expression in neurons.A similar reversal was seen by over-expressing Tuberous Sclerosis Complex (Tsc1,2) that negatively regulates TOR signaling as also by reduction of S6K activity.In comparison, the small bouton phenotype associated with VAP(wt) expression was reversed with Tsc1 knock down as well as S6K-CA expression.

View Article: PubMed Central - PubMed

Affiliation: Indian Institute of Science Education and Research, Pune 411021, India.

No MeSH data available.


Related in: MedlinePlus