Abstract
The primordial TOR pathway, known to control growth and cell proliferation, has still not been fully described for plants. Nevertheless, in maize, an insulin-like growth factor (ZmIGF) peptide has been reported to stimulate this pathway. This research provides further insight into the TOR pathway in maize, using a biochemical approach in cultures of fast-growing (FG) and slow-growing (SG) calli, as a model system. Our results revealed that addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation and increased the rate of ribosomal protein (RP) synthesis by the selective mobilization of RP mRNAs into polysomes. Furthermore, analysis of the phosphorylation status of the main TOR and S6K kinases from the TOR pathway revealed stimulation by ZmIGF or insulin, whereas rapamycin inhibited its activation. Remarkably, a putative maize insulin-like receptor was recognized by a human insulin receptor antibody, as demonstrated by immunoprecipitation from membrane protein extracts of maize callus. Furthermore, competition experiments between ZmIGF and insulin for the receptor site on maize protoplasts suggested structural recognition of the putative receptor by either effector. These data were confirmed by confocal immunolocalization within the cell membrane of callus cells. Taken together, these data indicate that cell growth and cell proliferation in maize depend on the activation of the TOR-S6K pathway through the interaction of an insulin-like growth factor and its receptor. This evidence suggests that higher plants as well as metazoans have conserved this biochemical pathway to regulate their growth, supporting the conclusion that it is a highly evolved conserved pathway.
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Claims 13
Claim · model-written summary
ZmIGF stimulated DNA synthesis in slow-growing maize callus.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis”
t0“Maize (Zea mays L.)”
Claim · model-written summary
Insulin stimulated DNA synthesis in slow-growing maize callus.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis”
t0“Maize (Zea mays L.)”
Claim · model-written summary
ZmIGF increased slow-growing callus growth rate through cell proliferation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation”
t0“Maize (Zea mays L.)”
Claim · model-written summary
Insulin increased slow-growing callus growth rate through cell proliferation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation”
t0“Maize (Zea mays L.)”
Claim · model-written summary
ZmIGF increased ribosomal protein synthesis through RP mRNA mobilization.
- Treatment
- ZmIGFe0
- Outcome
- rate of ribosomal protein (RP) synthesise0
- Direction
- increasede0
- Qualifier
- selective mobilization of RP mRNAs into polysomese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation and increased the rate of ribosomal protein (RP) synthesis by the selective mobilization of RP mRNAs into polysomes”
t0“Maize (Zea mays L.)”
Claim · model-written summary
Insulin increased ribosomal protein synthesis through RP mRNA mobilization.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of either ZmIGF or insulin to SG calli stimulated DNA synthesis and increased the growth rate through cell proliferation and increased the rate of ribosomal protein (RP) synthesis by the selective mobilization of RP mRNAs into polysomes”
t0“Maize (Zea mays L.)”
Claim · model-written summary
ZmIGF stimulated TOR and S6K phosphorylation.
- Treatment
- ZmIGFe0
- Outcome
- phosphorylation status of the main TOR and S6K kinasese0
- Direction
- stimulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“phosphorylation status of the main TOR and S6K kinases from the TOR pathway revealed stimulation by ZmIGF or insulin”
t0“Maize (Zea mays L.)”
Claim · model-written summary
Insulin stimulated TOR and S6K phosphorylation.
- Treatment
- insuline0
- Outcome
- phosphorylation status of the main TOR and S6K kinasese0
- Direction
- stimulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“phosphorylation status of the main TOR and S6K kinases from the TOR pathway revealed stimulation by ZmIGF or insulin”
t0“Maize (Zea mays L.)”
Claim · model-written summary
Rapamycin inhibited TOR pathway activation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rapamycin inhibited its activation”
t0“Maize (Zea mays L.)”
Claim · model-written summary
A human insulin receptor antibody recognized a putative maize insulin-like receptor.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a putative maize insulin-like receptor was recognized by a human insulin receptor antibody”
Claim · model-written summary
Competition experiments suggested that ZmIGF and insulin are both structurally recognized at the maize receptor site.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“competition experiments between ZmIGF and insulin for the receptor site on maize protoplasts suggested structural recognition of the putative receptor by either effector”
Claim · model-written summary
Confocal immunolocalization confirmed the receptor evidence at the callus cell membrane.
- Outcome
- confocal immunolocalization within the cell membrane of callus cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These data were confirmed by confocal immunolocalization within the cell membrane of callus cells”
t0“Maize (Zea mays L.)”
Claim · model-written summary
The authors conclude that maize cell growth and proliferation depend on TOR-S6K activation through growth-factor receptor interaction.
- Outcome
- cell growth and cell proliferatione0
- Qualifier
- activation of the TOR-S6K pathway through the interaction of an insulin-like growth factor and its receptore0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“cell growth and cell proliferation in maize depend on the activation of the TOR-S6K pathway through the interaction of an insulin-like growth factor and its receptor”
The same questions in other papers
insulin · quality: protein · Zea mays (maize)Results agree
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- positive
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insulin · growth · Zea mays (maize)Results agree
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- positive
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- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.