Context-specific regulation of transcription factor activity by MAP Kinase-mediated phosphorylation

01/03/2026 to 28/02/2029

The development of different tissue types relies in many cases on core signaling modules that are repeatedly used in different contexts.
These modules can be encoded by paralogous genes that are expressed in a tissue-specific manner or even rely on the same
genes. How seemingly identical signaling modules achieve different, context-specific outputs, however, is poorly understood. Deciphering
the molecular mechanisms that tailor core signaling modules to their context-specific function is therefore key to understanding how tissuespecificity
is achieved on a mechanistic level. In the proposed project, we want to understand how transcription factors can be controlled in
opposite manner in different cell types by the same MAP kinase-mediated phosphorylation, focusing on the class IIIb basic helix-loophelix
(bHLH) transcription factor INDUCER OF CBF EXPRESSION1 (ICE1, also named SCREAM). ICE1 functions as central hub for MAP
kinase signaling in very different contexts, such as embryogenesis, stomata development, endosperm breakdown and seed dormancy, as
well as cold stress acclimatization. In the case of embryogenesis and stomata development, identical phosphorylation events by the same
MAP kinase activates or represses ICE1 activity depending on the cellular context. In this project, we will decipher the molecular
mechanism behind this differential, cell-type specific regulation to broaden our general understanding transcription factor regulation in
the context of tissue specificity.