Feedback control of ErbB2 via ERK-mediated phosphorylation of a conserved threonine in the juxtamembrane domain

• Published in: Scientific reports Vol. 6; no. 1; p. 31502
• Main Authors: Kawasaki, Yuki, Sakimura, Ayaka, Park, Chul Min, Tomaru, Rika, Tanaka, Tomohiro, Ozawa, Tatsuhiko, Zhou, Yue, Narita, Kaori, Kishi, Hiroyuki, Muraguchi, Atsushi, Sakurai, Hiroaki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 17.08.2016; Nature Publishing Group
• Subjects: 631/67/395; 631/80/86/2368; 96/95; Alanine; Breast cancer; Breast Neoplasms - enzymology; Breast Neoplasms - genetics; Breast Neoplasms - pathology; Cell Line, Tumor; Epidermal growth factor receptors; ErbB protein; ErbB-2 protein; ErbB-3 protein; Extracellular signal-regulated kinase; Extracellular Signal-Regulated MAP Kinases - antagonists & inhibitors; Extracellular Signal-Regulated MAP Kinases - genetics; Extracellular Signal-Regulated MAP Kinases - metabolism; Feedback inhibition; Female; HEK293 Cells; Humanities and Social Sciences; Humans; Kinases; Metabolic pathways; Monoclonal antibodies; multidisciplinary; Multienzyme Complexes - genetics; Multienzyme Complexes - metabolism; Phosphorylation; Phosphorylation - genetics; Protein Domains; Protein-tyrosine kinase; Receptor, ErbB-2 - genetics; Receptor, ErbB-2 - metabolism; Receptor, ErbB-3 - genetics; Receptor, ErbB-3 - metabolism; Science; Threonine; Threonine - genetics; Threonine - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep31502

Tyrosine kinase activity of the asymmetric EGFR homodimer is negatively regulated via ERK-mediated phosphorylation of Thr-669 in the juxtamembrane domain. In the present study, we investigated in human breast cancer cells whether a similar mechanism plays a role in the feedback regulation of the ErbB2/ErbB3 heterodimer, the most potent ErbB receptor dimer. Constitutive tyrosine phosphorylation of ErbB2 and ErbB3 was significantly decreased in phorbol ester- and growth factor-treated BT-474 and MDA-MB-453 cells. In contrast to the decreased tyrosine phosphorylation, Phos-tag Western blot analysis revealed that TPA induced phosphorylation of ErbB2 in an ERK-dependent manner. The target threonine residue corresponding to EGFR Thr-669 and the surrounding residues are highly conserved in ErbB2, but not in ErbB3. Therefore, we demonstrated ERK-mediated phosphorylation of ErbB2 at Thr-677 by generating phospho-specific monoclonal antibodies. Moreover, treatment with trametinib and SCH772984, inhibitors of the MEK-ERK pathway and substitution of Thr-677 to alanine impaired the feedback inhibition of ErbB2 and ErbB3. These results demonstrated that ERK-mediated phosphorylation of the conserved threonine is a common mechanism for the negative feedback control of active ErbB receptor dimers.