PT  - JOURNAL ARTICLE
AU  - Eduardo D. Sontag
TI  - Bell-shaped dose response for a system with no IFFLs
AID  - 10.1101/2020.11.17.387605
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.11.17.387605
4099  - http://biorxiv.org/content/early/2020/12/02/2020.11.17.387605.short
4100  - http://biorxiv.org/content/early/2020/12/02/2020.11.17.387605.full
AB  - It is well known that the presence of an incoherent feedforward loop (IFFL) in a network may give rise to a steady state non-monotonic dose response. This note shows that the converse implication does not hold. It gives an example of a three-dimensional system that has no IFFLs, yet its dose response is bell-shaped. It also studies under what conditions the result is true for two-dimensional systems, in the process recovering, in far more generality, a result given in the T-cell activation literature.Competing Interest StatementThe authors have declared no competing interest.