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Re-examination of Dietary Amino Acid Sensing Reveals a GCN2-Independent Mechanism.

Leib DE, Knight ZA - Cell Rep (2015)

Bottom Line: Animals cannot synthesize nine essential amino acids (EAAs) and must therefore obtain them from food.In contrast to previous results, we find that mice cannot rapidly identify threonine- or leucine-deficient food in common feeding paradigms.These behaviors are independent of the proposed amino acid sensor GCN2, pointing to the existence of an undescribed mechanism for rapid sensing of dietary EAAs.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA.

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Rapid Detection of Lysine-, but Not Threonine- or Leucine-, Deficient Diets in a Choice Assay(A) Dietary choice paradigm in (B)–(F).(B) Wild-type mice (n = 5) showed no significant preference for T-def or novel control food presented as a choice after 3 hr of feeding and overnight.(C) Wild-type mice (n = 9) consumed more TL-def food than control after 3 hr of feeding (p = 0.03) but showed no preference overnight.(D) Wild-type mice (n = 7) consumed less AA-dev food than control after 3 hr of feeding (p = 0.0007) and overnight (p < 0.0001).(E) Wild-type mice (n = 5) consumed significantly less AA-dev than TL-def food after 3 hr of feeding (p = 0.0115) and overnight (p < 0.0001).(F) Wild-type (n = 12) and Gcn2−/− (n = 5) mice consumed significantly less K-def food than control after 3 hr feeding (p = 0.03) and overnight (p < 0.0001), with no significant effect of genotype or interaction between diet and genotype.See also Figure S4.
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Figure 3: Rapid Detection of Lysine-, but Not Threonine- or Leucine-, Deficient Diets in a Choice Assay(A) Dietary choice paradigm in (B)–(F).(B) Wild-type mice (n = 5) showed no significant preference for T-def or novel control food presented as a choice after 3 hr of feeding and overnight.(C) Wild-type mice (n = 9) consumed more TL-def food than control after 3 hr of feeding (p = 0.03) but showed no preference overnight.(D) Wild-type mice (n = 7) consumed less AA-dev food than control after 3 hr of feeding (p = 0.0007) and overnight (p < 0.0001).(E) Wild-type mice (n = 5) consumed significantly less AA-dev than TL-def food after 3 hr of feeding (p = 0.0115) and overnight (p < 0.0001).(F) Wild-type (n = 12) and Gcn2−/− (n = 5) mice consumed significantly less K-def food than control after 3 hr feeding (p = 0.03) and overnight (p < 0.0001), with no significant effect of genotype or interaction between diet and genotype.See also Figure S4.

Mentions: In a choice assay controlling for dietary novelty (Figure 3A), wild-type mice had no preference for control over T-def chow (Figure 3B). When given a choice between control and doubly deficient TL-def chow, mice again had no preference for control and in fact consumed more TL-def food (Figure 3C). However, mice did show a strong preference for control over AA-def food, consuming in most cases an undetectable amount of AA-def food in 3 hr (0.47 ± 0.07 g versus 0 ± 0 g) and overnight (3.4 ± 0.1 g versus 0.03 ± 0.03 g; Figure 3D). Thus, this choice assay can robustly detect preference between two diets, but mice do not identify and reject T-def or L-def diets on a timescale of up to 21 hr when given a choice.


Re-examination of Dietary Amino Acid Sensing Reveals a GCN2-Independent Mechanism.

Leib DE, Knight ZA - Cell Rep (2015)

Rapid Detection of Lysine-, but Not Threonine- or Leucine-, Deficient Diets in a Choice Assay(A) Dietary choice paradigm in (B)–(F).(B) Wild-type mice (n = 5) showed no significant preference for T-def or novel control food presented as a choice after 3 hr of feeding and overnight.(C) Wild-type mice (n = 9) consumed more TL-def food than control after 3 hr of feeding (p = 0.03) but showed no preference overnight.(D) Wild-type mice (n = 7) consumed less AA-dev food than control after 3 hr of feeding (p = 0.0007) and overnight (p < 0.0001).(E) Wild-type mice (n = 5) consumed significantly less AA-dev than TL-def food after 3 hr of feeding (p = 0.0115) and overnight (p < 0.0001).(F) Wild-type (n = 12) and Gcn2−/− (n = 5) mice consumed significantly less K-def food than control after 3 hr feeding (p = 0.03) and overnight (p < 0.0001), with no significant effect of genotype or interaction between diet and genotype.See also Figure S4.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836942&req=5

Figure 3: Rapid Detection of Lysine-, but Not Threonine- or Leucine-, Deficient Diets in a Choice Assay(A) Dietary choice paradigm in (B)–(F).(B) Wild-type mice (n = 5) showed no significant preference for T-def or novel control food presented as a choice after 3 hr of feeding and overnight.(C) Wild-type mice (n = 9) consumed more TL-def food than control after 3 hr of feeding (p = 0.03) but showed no preference overnight.(D) Wild-type mice (n = 7) consumed less AA-dev food than control after 3 hr of feeding (p = 0.0007) and overnight (p < 0.0001).(E) Wild-type mice (n = 5) consumed significantly less AA-dev than TL-def food after 3 hr of feeding (p = 0.0115) and overnight (p < 0.0001).(F) Wild-type (n = 12) and Gcn2−/− (n = 5) mice consumed significantly less K-def food than control after 3 hr feeding (p = 0.03) and overnight (p < 0.0001), with no significant effect of genotype or interaction between diet and genotype.See also Figure S4.
Mentions: In a choice assay controlling for dietary novelty (Figure 3A), wild-type mice had no preference for control over T-def chow (Figure 3B). When given a choice between control and doubly deficient TL-def chow, mice again had no preference for control and in fact consumed more TL-def food (Figure 3C). However, mice did show a strong preference for control over AA-def food, consuming in most cases an undetectable amount of AA-def food in 3 hr (0.47 ± 0.07 g versus 0 ± 0 g) and overnight (3.4 ± 0.1 g versus 0.03 ± 0.03 g; Figure 3D). Thus, this choice assay can robustly detect preference between two diets, but mice do not identify and reject T-def or L-def diets on a timescale of up to 21 hr when given a choice.

Bottom Line: Animals cannot synthesize nine essential amino acids (EAAs) and must therefore obtain them from food.In contrast to previous results, we find that mice cannot rapidly identify threonine- or leucine-deficient food in common feeding paradigms.These behaviors are independent of the proposed amino acid sensor GCN2, pointing to the existence of an undescribed mechanism for rapid sensing of dietary EAAs.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA.

Show MeSH
Related in: MedlinePlus