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Active ERK2 is sufficient to mediate growth arrest and differentiation signaling. FEBS J 2015 Mar;282(6):1017-30

Date

02/03/2015

Pubmed ID

25639353

Pubmed Central ID

PMC4368470

DOI

10.1111/febs.13197

Scopus ID

2-s2.0-84925621653   12 Citations

Abstract

Although extracellular signal-regulated kinases (ERK1/2) have been shown to be required in Raf/MEK/ERK pathway signaling, its sufficiency for mediating the pathway signaling has not been firmly established. In an effort to address this, we evaluated previously described ERK2 mutants that exhibit enhanced autophosphorylation of TEY sites in the activation loop in terms of their ability to induce growth arrest and differentiation in LNCaP and PC12 cells. We demonstrate that expression of ERK2-L73P/S151D, containing Lys73Pro and Ser151Asp substitutions that synergistically promote ERK autophosphorylation, is sufficient to induce growth arrest and differentiation, whereas expression of ERK2-I84A and ERK2-R65S/D319N is not as effective. When compared to the constitutively active MEK1-ΔN3/S218E/S222D, expression of ERK2-L73P/S151D only mildly increased ERK kinase activity in cells, as assessed using the ERK substrates p90(RSK) and ETS domain-containing protein (ELK1). However, ERK2-L73P/S151D expression effectively induced down-regulation of androgen receptors, Retinoblastoma (Rb) protein and E2F1 transcription factor, and up-regulation of p16(INK4A) and p21(CIP1), accompanied by cell-cycle arrest and morphological differentiation in LNCaP cells and neurite-like processes in PC12 cells. These effects and the TEY site phosphorylation of ERK2-L73P/S151D were abrogated upon introduction of the active site-disabling Lys52Arg mutation, suggesting that its autoactivation drives this signaling. Moreover, introduction of mutations Asp316/319Ala or Asp319Asn, which impair the common docking site/D-domain-based physical interaction of ERK, did not significantly affect ERK2-L73P/S151D signaling, suggesting that ERK2 mediates growth arrest and differentiation independently of the conventional ERK-target interaction mechanism. Thus, our study presents convincing evidence of ERK sufficiency for Raf/MEK/ERK signaling.

Author List

Wu PK, Hong SK, Yoon SH, Park JI

Authors

Jong-In Park PhD Professor in the Biochemistry department at Medical College of Wisconsin
Pui Kei Wu PhD Instructor in the Biochemistry department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Binding Sites
Cell Cycle
Cell Differentiation
Cell Line, Tumor
Cell Proliferation
Cellular Senescence
HEK293 Cells
Humans
MAP Kinase Signaling System
Male
Mutation
PC12 Cells
Phosphorylation
Plasmids
Protein Structure, Tertiary
Rats
Receptors, Androgen
Response Elements
raf Kinases
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a