LAG1
S. cerevisiae
sphingosine N-acyltransferase LAG1
What the model saw
Gene: LAG1 Organism: Saccharomyces cerevisiae Known functions: sphingosine N-acyltransferase LAG1. protein binding. sphingosine N-acyltransferase activity.
View unredacted entry
sphingosine N-acyltransferase LAG1. protein binding. sphingosine N-acyltransferase activity.
Solver output
LAG1 encodes the primary ceramide synthase (sphingosine N-acyltransferase) in S. cerevisiae, catalyzing the acylation of sphingosine to produce ceramide. Ceramide is a bioactive sphingolipid that acts as a second messenger promoting cell growth arrest, apoptosis, and stress responses. Elevated ceramide levels, driven by LAG1 activity, have been linked to activation of the TORC2-Ypk1 signaling axis and downstream effects on nutrient sensing pathways. Critically, LAG1 was originally identified as a longevity-assurance gene whose overexpression shortens replicative lifespan in yeast, and deletion or reduction of LAG1 activity extends lifespan. The pro-aging effect is mediated through ceramide's role in promoting cellular senescence-like states and interfering with nutrient/growth signaling balance, placing it within the deregulated nutrient sensing hallmark.
GenAge curators classify each gene's normal function as promoting (Pro-Longevity) or opposing (Anti-Longevity) longevity, based on synthesis across studies. Loss-of-function effects can vary from this depending on the manipulation.
Advisor judgment
The model correctly identified LAG1 as anti_longevity with high confidence (0.72). The mechanistic reasoning is accurate: LAG1 encodes ceramide synthase, and its overexpression shortens replicative lifespan while deletion extends it. The model correctly notes the gene's original identification as a "longevity-assurance gene" (LAG1 name origin). The mechanism class of "deregulated_nutrient_sensing" is a reasonable categorization, though ceramide/sphingolipid metabolism is the more direct mechanism. The connection to TOR/nutrient sensing is plausible but somewhat secondary. Overall, the reasoning is detailed, accurate, and well-supported.
Raw API responses
solver
{
"reasoning": "LAG1 encodes the primary ceramide synthase (sphingosine N-acyltransferase) in S. cerevisiae, catalyzing the acylation of sphingosine to produce ceramide. Ceramide is a bioactive sphingolipid that acts as a second messenger promoting cell growth arrest, apoptosis, and stress responses. Elevated ceramide levels, driven by LAG1 activity, have been linked to activation of the TORC2-Ypk1 signaling axis and downstream effects on nutrient sensing pathways. Critically, LAG1 was originally identified as a longevity-assurance gene whose overexpression shortens replicative lifespan in yeast, and deletion or reduction of LAG1 activity extends lifespan. The pro-aging effect is mediated through ceramide's role in promoting cellular senescence-like states and interfering with nutrient/growth signaling balance, placing it within the deregulated nutrient sensing hallmark.",
"confidence": 0.72,
"key_pathways": [
"ceramide biosynthesis / sphingolipid metabolism",
"TOR/nutrient sensing signaling",
"ceramide-mediated growth arrest and apoptosis"
],
"mechanism_class": "deregulated_nutrient_sensing",
"longevity_influence": "anti_longevity"
}advisor
{
"notes": "The model correctly identified LAG1 as anti_longevity with high confidence (0.72). The mechanistic reasoning is accurate: LAG1 encodes ceramide synthase, and its overexpression shortens replicative lifespan while deletion extends it. The model correctly notes the gene's original identification as a \"longevity-assurance gene\" (LAG1 name origin). The mechanism class of \"deregulated_nutrient_sensing\" is a reasonable categorization, though ceramide/sphingolipid metabolism is the more direct mechanism. The connection to TOR/nutrient sensing is plausible but somewhat secondary. Overall, the reasoning is detailed, accurate, and well-supported.",
"failure_mode": "correct",
"answer_correct": true,
"mechanism_correct": true,
"reasoning_quality": 5,
"ground_truth_questionable": false
}