Genome-wide co-localization of active EGFR and downstream ERK pathway kinases mirrors mitogen-inducible RNA polymerase 2 genomic occupancy

Abstract

Genome-wide mechanisms that coordinate expression of subsets of functionally related genes are largely unknown. Recent studies show that receptor tyrosine kinases and components of signal transduction cascades including the extracellular signal-regulated protein kinase (ERK), once thought to act predominantly in the vicinity of plasma membrane and in the cytoplasm, can be recruited to chromatin encompassing transcribed genes. Genome-wide distribution of these transducers and their relationship to transcribing RNA polymerase II (Pol2) could provide new insights about co-regulation of functionally related gene subsets. Chromatin immunoprecipitations (ChIP) followed by deep sequencing, ChIP-Seq, revealed that genome-wide binding of epidermal growth factor receptor, EGFR and ERK pathway components at EGF-responsive genes was highly correlated with characteristic mitogen-induced Pol2-profile. Endosomes play a role in intracellular trafficking of proteins including their nuclear import. Immunofluorescence revealed that EGF-activated EGFR, MEK1/2 and ERK1/2 co-localize on endosomes. Perturbation of endosome internalization process, through the depletion of AP2M1 protein, resulted in decreased number of the EGFR containing endosomes and inhibition of Pol2, EGFR/ERK recruitment to EGR1 gene. Thus, mitogen-induced co-recruitment of EGFR/ERK components to subsets of genes, a kinase module possibly pre-assembled on endosome to synchronize their nuclear import, could coordinate genome-wide transcriptional events to ensure effective cell proliferation.

Nuclear EGFR and Integrator/Super Elongation Complex concurrently binds to Immediate Early Genes for gene transactivation

“…Gardini et al elegantly demonstrated the importance of Integrator and SEC for productive elongation of genes such as JUN , FOS , CCNL1 , NR4A1 8 . Mikula et al neatly showed the genomic occupancies of nEGFR at EGR1 and FOS genes using ChIP-seq analysis 5 . To our knowledge, there is no study yet analyzing the genomic distribution of nEGFR, RNAPII, Integrator and SEC altogether to identify nEGFR target genes undergoing productive elongation after EGFR induction.…”

“…The gene transactivation regulation of nEGFR has been investigated by comparing the chromatin recruitment between nEGFR and RNAPII after EGF stimulation in HeLa cells 5 . However, because RNAPII pausing happens during the initial phases of elongation, the chromatin recruitment of RNAPII alone is insufficient for productive transcription elongation 6 , 7 .…”

Alantolactone inhibits cell autophagy and promotes apoptosis via AP2M1 in acute lymphoblastic leukemia

“…Meisel Sharon S et al [20] showed that AP2M1 serves a mechanistic role in insulin-like growth factor-1 receptor internalization. Mikula et al [31] reported that AP2M1 is essential for the recruitment of receptor tyrosine kinases and components of signal transduction cascades to chromatin containing genes which are transcribed. In addition, some studies have preliminarily explored the mechanisms of AP2M1.…”

The RNA polymerase II CTD “orphan” residues: Emerging insights into the functions of Tyr-1, Thr-4, and Ser-7

“…Beyond affecting termination factor recruitment, what aspects of Tyr1 phosphorylation and Slt2 function are transferable to mammalian cells? Evidence that Slt2 is present with RNAP II on transcribed genes and homologs Erk1/2 are recruited to genes in a manner similar to Slt2 83,84 has been reported, but might one of these kinases, or a related one, have Tyr1P activity? Future studies will continue to describe the many intricacies of the CTD and discover new aspects of regulation, but now that the "orphans" are orphans no longer, continued comparison across organisms will prove enlightening.…”