TY  - JOUR
A1  - Schmidt-Glenewinkel, Hannah
A1  - Vacheva, Ivayla
A1  - Hoeller, Daniela
A1  - Đikić, Ivan
A1  - Eils, Roland
T1  - An ultrasensitive sorting mechanism for EGF receptor endocytosis
T2  - BMC systems biology
N2  - Background The EGF receptor has been shown to internalize via clathrin-independent endocytosis (CIE) in a ligand concentration dependent manner. From a modeling point of view, this resembles an ultrasensitive response, which is the ability of signaling networks to suppress a response for low input values and to increase to a pre-defined level for inputs exceeding a certain threshold. Several mechanisms to generate this behaviour have been described theoretically, the underlying assumptions of which, however, have not been experimentally demonstrated for the EGF receptor internalization network. Results Here, we present a mathematical model of receptor sorting into alternative pathways that explains the EGF-concentration dependent response of CIE. The described mechanism involves a saturation effect of the dominant clathrin-dependent endocytosis pathway and implies distinct steady-states into which the system is forced for low vs high EGF stimulations. The model is minimal since no experimentally unjustified reactions or parameter assumptions are imposed. We demonstrate the robustness of the sorting effect for large parameter variations and give an analytic derivation for alternative steady-states that are reached. Further, we describe extensibility of the model to more than two pathways which might play a role in contexts other than receptor internalization. Conclusions Our main result is that a scenario where different endocytosis routes consume the same form of receptor corroborates the observation of a clear-cut, stimulus dependent sorting. This is especially important since a receptor modification discriminating between the pathways has not been found. The model is not restricted to EGF receptor internalization and might account for ultrasensitivity in other cellular contexts.
Y1  - 2008
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/5687
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30-54523
SN  - 1752-0509
N1  - © 2008 Schmidt-Glenewinkel et al., licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
VL  - 2
IS  - 32
SP  - 1
EP  - 14
PB  - BioMed Central
CY  - London
ER  -