ERK5 in cell proliferation and neuronal
Mitogen-activated protein kinase 7 (ERK5 (MAPK7)) is
involved in regulation of various cellular processes first of all cell proliferation and
survival. ERK5 (MAPK7) is a mitogen-activated protein kinase
regulated by a wide range of mitogens and cellular stresses .
Epidermal growth factor (EGF) and Nerve growth factor
(NGF) could activate ERK5
(MAPK7) through Ras-dependent mechanism. Harvey rat sarcoma viral oncogene
homolog (H-Ras) activation triggers the Raf-1 murine
leukemia viral oncogene homolog 1 (c-Raf-1)/ Mitogen-activated protein kinase kinase 5
(MAP2K5 (MEK5))/ ERK5 (MAPK7)
pathway. Subsequently ERK5 (MAPK7) phosphorylates and
activates Elk-4. Elk-4
activates FBJ murine osteosarcoma viral oncogene homolog
(c-Fos) transcription leading to cell proliferation , .
NGF binding to its receptor Neurotrophic tyrosine kinase,
receptor, type 1 (TrkA) stimulates
Sequestosome 1(p62) binding to
TrkA. Sequestosome 1(p62)
-TrkA interaction is required for the internalization of the
receptor followed by activation of atypical PKCs: PKC-zeta
and PKC-lambda/iota. Atypical PKCs bind to
(MAP2K5 (MEK5)) but they are unable to directly
phosphorylate MAP2K5 (MEK5) and activate this kinase most
likely by promoting its autophosphorylation. MAP2K5 (MEK5)
is essential activator of ERK5 (MAPK7). Activation of
ERK5 (MAPK7) through atypical PKCs leads to Myocyte enhancer
factor 2C (MEF2C) phosphorylation and activation by
ERK5 (MAPK7). MEF2C activates
Jun oncogene (c-Jun) transcription which is essential
component in proliferative signaling , .
Brain-derived neurotrophic factor (BDNF) activates
cascade by Rap1-dependent mechanism and signals to neuronal survival. ERK5
(MAPK7) provides neuronal survival through cAMP responsive element binding
protein 1 (CREB1) phosphorylation and activation which is
probably mediated by Ribosomal protein S6 kinase, 90kDa, polypeptide 3
(p90RSK2(RPS6KA3)) , .
Stress (such as H2O2 application) activates Lymphocyte-specific protein tyrosine
kinase (Lck) which in turn phosphorylates and activates SH2
domain protein 2A (TSAD). TSAD
binds to Mitogen-activated protein kinase kinase kinase 2 (MAP3K2
(MEKK2)) activates it and triggers MAP3K2
(MEKK2)/ MAP2K5 (MEK5)/ ERK5
(MAPK7) cascade. TSAD is also involved in
activation of mentioned cascade by EGF but exact mechanism isn't clear , .
Apart pathways regulated by stress and growth factors ERK5
(MAPK7) activity is stimulated by WNK lysine deficient protein kinase 3
(WNK) through phosphorylation and activation of
MAP3K2 (MEKK2) and Mitogen-activated protein kinase kinase
kinase 3 (MAP3K3). Though upstream activators of WNK for
this pathway are yet unknown .
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Regulation of cellular functions by the ERK5 signalling pathway.
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Activation of the protein kinase ERK5/BMK1 by receptor tyrosine kinases. Identification and characterization of a signaling pathway to the nucleus.
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Contribution of the ERK5/MEK5 pathway to Ras/Raf signaling and growth control.
The Journal of biological chemistry 1999 Oct 29;274(44):31588-92
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MEK5, a new target of the atypical protein kinase C isoforms in mitogenic signaling.
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Association of the atypical protein kinase C-interacting protein p62/ZIP with nerve growth factor receptor TrkA regulates receptor trafficking and Erk5 signaling.
The Journal of biological chemistry 2003 Feb 14;278(7):4730-9
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Neurotrophins use the Erk5 pathway to mediate a retrograde survival response.
Nature neuroscience 2001 Oct;4(10):981-8
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Brain-derived neurotrophic factor activates ERK5 in cortical neurons via a Rap1-MEKK2 signaling cascade.
The Journal of biological chemistry 2006 Nov 24;281(47):35965-74
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MEKK2 associates with the adapter protein Lad/RIBP and regulates the MEK5-BMK1/ERK5 pathway.
The Journal of biological chemistry 2001 Feb 16;276(7):5093-100
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MEK kinase 2 and the adaptor protein Lad regulate extracellular signal-regulated kinase 5 activation by epidermal growth factor via Src.
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WNK1 activates ERK5 by an MEKK2/3-dependent mechanism.
The Journal of biological chemistry 2004 Feb 27;279(9):7826-31