1. Two competing models for Rab domain identity generation and endosome conversion.
Two competing models for Rab domain identity generation and endosome conversion. Green arrows denote reported interactions and red arrows denote proposed interactions that each may be essential (solid arrow) or just tolerated (dashed arrow). (A) Model 1 corresponds to a toggle switch that can switch off Rab5 as a result of weakened activation of Rab5 by its GEF (solid green arrow). Switching on of Rab7 follows if the repression (red arrow) by Rab5 becomes inferior to the activation (green dashed arrows). (B) Model 2 represents a cut‐out switch that can switch off Rab5 as a result of enhanced (e.g. cargo‐dependent, pH‐dependent) activation of Rab5, as Rab5 fosters Rab7 activity (upper green arrow) to pass a threshold above which Rab7 self‐sustains (right green arrow) its own activation. Rab7 activation at supra‐threshold values strongly suppresses Rab5 (red arrow).
Perla Del Conte‐Zerial et al. Mol Syst Biol 2008;4:206
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