Drosophila S6 kinase: a regulator of cell size

Montagne J, Stewart MJ, Stocker H, Hafen E, Kozma SC, Thomas G · 1999 · Science · Atlas ID MON1999

What this study shows

The authors made fruit flies lacking the S6 kinase gene (dS6K) and followed their development. These flies developed with a strong delay and ended up much smaller. The smaller body came from smaller cells, not from fewer cells. The effect was cell-autonomous, seen across larval development, and differed from the phenotype of ribosomal protein (Minute) mutants. The authors concluded that S6K controls cell size in flies without changing cell number. Boundary: Drosophila only; genetic loss of S6K from the start of development, so it does not show what happens when S6K is lowered in adult animals or in mammals.

Abstract

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Cell proliferation requires cell growth; that is, cells only divide after they reach a critical size. However, the mechanisms by which cells grow and maintain their appropriate size have remained elusive. Drosophila deficient in the S6 kinase gene (dS6K) exhibited an extreme delay in development and a severe reduction in body size. These flies had smaller cells rather than fewer cells. The effect was cell-autonomous, displayed throughout larval development, and distinct from that of ribosomal protein mutants (Minutes).

Read the full abstract on PubMed →

At a glance

Evidence type	A Animal model Marked A because it is an animal intervention or observation study measuring an organismal outcome (model: Drosophila melanogaster dS6K-deficient mutants; mosaic (clonal) analysis of wing and larval cells); the code names the system studied -- animal work can be rigorous and still not be human data.
Study type	4 - Animal Study
Model system	Drosophila melanogaster dS6K-deficient mutants; mosaic (clonal) analysis of wing and larval cells
Journal	Science
Year	1999
Peer reviewed	Yes
Record last updated	2026-10-01
Source	DOI 10.1126/science.285.5436.2126 · PMID 10497130

Extracted findings

These fields were extracted from the paper with AI assistance and have not been checked against the source. Read them as a pointer into the paper, not as curated claims; where they disagree with the curated summary above, the curated summary stands.

Intervention	dS6K gene deletion
Target	Body size; cell size; developmental timing
Model	Drosophila melanogaster
Effect	Loss of dS6K -> smaller cells and body, delayed development

In the Atlas

Cite this paper

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Montagne, J., Stewart, M. J., Stocker, H., Hafen, E., Kozma, S. C., & Thomas, G. (1999). Drosophila S6 kinase: a regulator of cell size. Science. https://doi.org/10.1126/science.285.5436.2126

@article{MON1999,
  author       = {Montagne, J. and Stewart, M. J. and Stocker, H. and Hafen, E. and Kozma, S. C. and Thomas, G.},
  title        = {{Drosophila S6 kinase: a regulator of cell size}},
  journal      = {Science},
  year         = {1999},
  doi          = {10.1126/science.285.5436.2126},
  note         = {PMID: 10497130},
}

Cite this Atlas record

The record is the Atlas's own work — the evidence label, the extracted findings and the links. It is cited as part of the dataset, not as the paper.

Barton, O. (2026). Oliver's mTOR Atlas (record MON1999) [Data set]. https://mtor-atlas.org/study/MON1999/ · Dataset DOI 10.5281/zenodo.22059963

@misc{atlas_MON1999,
  author       = {Barton, Oliver},
  title        = {{Oliver's mTOR Atlas}, record MON1999},
  howpublished = {Data set},
  year         = {2026},
  url          = {https://mtor-atlas.org/study/MON1999/},
  doi          = {10.5281/zenodo.22059963}
}

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