MAPK signaling was once considered a linear and relatively simple receptor-to-nucleus pathway [31 33].
A dCas9 system fused to the KRAB transcription repressing domain has been used to confirm the function of LRP8-Reelin-regulated neuronal enhancers in cortical neurons and lead to the discovery of a novel synapse-to-nucleus pathway related to glutamatergic signaling [ 89].
However, because NF-treated seedlings retain their ability to sense and respond to Fe supply (Supplementary Figures 13 and 14), the Fe sensor is unlikely to be encoded by a PhANG, and more generally might not be under the control of the described plastid-to-nucleus pathways.
Here we report that primary epithelial cells restrict the amount of phospho-ERK localized in the nucleus after pathway stimulation, although the cells obviously have an intact Ras/MAPK signaling pathway and the means to activate ERK.
Although some enzymes responsible for the synthesis of these complex SL have been detected in e.g. the nucleus, this pathway is mainly localized in the Golgi apparatus.
In contrast, thapsigargin treatment promotes translocation of AIF (apoptosis inducing factor) to the nucleus, a pathway known to be activated by increased intracellular Ca2 +.
PPR and RRM proteins are reportedly involved in a wide range of different post-transcriptional processes in plant organelles [ 33- 35] and may also affect nuclear gene expression by plastid to nucleus signaling pathway [ 36].
The Last Eukaryotic Common Ancestor (LECA) possessed mitochondria, a nucleus, metabolic pathways that included glycolysis, and the pentose phosphate pathway, as well as a cell cycle regulated by cyclins and cyclin-dependent kinases [ 32, 33].
Factors that adversely affect ER homeostasis cause ER stress and initiate an ER-to-nucleus signaling pathway, termed the unfolded protein response (UPR).
Consistent with these observations is that PDR1 and PDR3 in S. cerevisiae are known to participate into the mitochondria-nucleus signalling pathway [21], which may also be applied to CgPDR1.
