Ras-mutant cancer cells display B-Raf binding to ras that activates extracellular signal-regulated kinase and is inhibited by protein kinase a phosphorylation

Yanping Li, Maho Takahashi, Philip Stork

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The small G protein Ras regulates proliferation through activation of the mitogen-activated protein (MAP) kinase (ERK) cascade. The first step of Ras-dependent activation of ERK signaling is Ras binding to members of the Raf family of MAP kinase kinase kinases, C-Raf and B-Raf. Recently, it has been reported thatin melanoma cells harboring oncogenic Ras mutations, B-Raf does not bind to Ras and does not contribute to basal ERK activation. For other types of Ras-mutant tumors, the relative contributions of C-Raf and B-Raf are not known. We examined non-melanoma cancer cell lines containing oncogenic Ras mutations and express both C-Raf and B-Raf isoforms, including the lung cancer cell line H1299 cells. Both B-Raf and C-Raf were constitutively bound to oncogenic Ras and contributedtoRas-dependent ERK activation. Ras bindingto B-Raf and C-Raf were both subject to inhibition by the cAMP-dependent protein kinase PKA. cAMP inhibited the growth of H1299 cells and Ras-dependent ERK activation via PKA. PKA inhibited the binding of Ras to both C-Raf and B-Raf through phosphorylations of C-Raf at Ser-259 and B-Raf at Ser-365, respectively. These studies demonstrate thatinnon-melanocytic Ras-mutant cancer cells, Ras signalingtoB-Rafis a significant contributor to ERK activation and that the B-Raf pathway, like that of C-Raf, is a target for inhibition by PKA. We suggest that cAMP and hormones coupled to cAMP may prove useful in dampening the effects of oncogenic Ras in non-melanocytic cancer cells through PKA-dependent actions on B-Raf as well as C-Raf.

Original languageEnglish (US)
Pages (from-to)27646-27657
Number of pages12
JournalJournal of Biological Chemistry
Volume288
Issue number38
DOIs
StatePublished - Sep 20 2013

Fingerprint

Phosphorylation
Extracellular Signal-Regulated MAP Kinases
Protein Kinases
Chemical activation
Cells
Neoplasms
MAP Kinase Kinase Kinases
Cell Line
Mutation
Monomeric GTP-Binding Proteins
Cyclic AMP-Dependent Protein Kinases
Mitogen-Activated Protein Kinases
Melanoma
Lung Neoplasms
Protein Isoforms
Tumors
Hormones
Growth

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

@article{1005a4814d6a4874b0f85dbb5110dc59,
title = "Ras-mutant cancer cells display B-Raf binding to ras that activates extracellular signal-regulated kinase and is inhibited by protein kinase a phosphorylation",
abstract = "The small G protein Ras regulates proliferation through activation of the mitogen-activated protein (MAP) kinase (ERK) cascade. The first step of Ras-dependent activation of ERK signaling is Ras binding to members of the Raf family of MAP kinase kinase kinases, C-Raf and B-Raf. Recently, it has been reported thatin melanoma cells harboring oncogenic Ras mutations, B-Raf does not bind to Ras and does not contribute to basal ERK activation. For other types of Ras-mutant tumors, the relative contributions of C-Raf and B-Raf are not known. We examined non-melanoma cancer cell lines containing oncogenic Ras mutations and express both C-Raf and B-Raf isoforms, including the lung cancer cell line H1299 cells. Both B-Raf and C-Raf were constitutively bound to oncogenic Ras and contributedtoRas-dependent ERK activation. Ras bindingto B-Raf and C-Raf were both subject to inhibition by the cAMP-dependent protein kinase PKA. cAMP inhibited the growth of H1299 cells and Ras-dependent ERK activation via PKA. PKA inhibited the binding of Ras to both C-Raf and B-Raf through phosphorylations of C-Raf at Ser-259 and B-Raf at Ser-365, respectively. These studies demonstrate thatinnon-melanocytic Ras-mutant cancer cells, Ras signalingtoB-Rafis a significant contributor to ERK activation and that the B-Raf pathway, like that of C-Raf, is a target for inhibition by PKA. We suggest that cAMP and hormones coupled to cAMP may prove useful in dampening the effects of oncogenic Ras in non-melanocytic cancer cells through PKA-dependent actions on B-Raf as well as C-Raf.",
author = "Yanping Li and Maho Takahashi and Philip Stork",
year = "2013",
month = "9",
day = "20",
doi = "10.1074/jbc.M113.463067",
language = "English (US)",
volume = "288",
pages = "27646--27657",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "38",

}

TY - JOUR

T1 - Ras-mutant cancer cells display B-Raf binding to ras that activates extracellular signal-regulated kinase and is inhibited by protein kinase a phosphorylation

AU - Li, Yanping

AU - Takahashi, Maho

AU - Stork, Philip

PY - 2013/9/20

Y1 - 2013/9/20

N2 - The small G protein Ras regulates proliferation through activation of the mitogen-activated protein (MAP) kinase (ERK) cascade. The first step of Ras-dependent activation of ERK signaling is Ras binding to members of the Raf family of MAP kinase kinase kinases, C-Raf and B-Raf. Recently, it has been reported thatin melanoma cells harboring oncogenic Ras mutations, B-Raf does not bind to Ras and does not contribute to basal ERK activation. For other types of Ras-mutant tumors, the relative contributions of C-Raf and B-Raf are not known. We examined non-melanoma cancer cell lines containing oncogenic Ras mutations and express both C-Raf and B-Raf isoforms, including the lung cancer cell line H1299 cells. Both B-Raf and C-Raf were constitutively bound to oncogenic Ras and contributedtoRas-dependent ERK activation. Ras bindingto B-Raf and C-Raf were both subject to inhibition by the cAMP-dependent protein kinase PKA. cAMP inhibited the growth of H1299 cells and Ras-dependent ERK activation via PKA. PKA inhibited the binding of Ras to both C-Raf and B-Raf through phosphorylations of C-Raf at Ser-259 and B-Raf at Ser-365, respectively. These studies demonstrate thatinnon-melanocytic Ras-mutant cancer cells, Ras signalingtoB-Rafis a significant contributor to ERK activation and that the B-Raf pathway, like that of C-Raf, is a target for inhibition by PKA. We suggest that cAMP and hormones coupled to cAMP may prove useful in dampening the effects of oncogenic Ras in non-melanocytic cancer cells through PKA-dependent actions on B-Raf as well as C-Raf.

AB - The small G protein Ras regulates proliferation through activation of the mitogen-activated protein (MAP) kinase (ERK) cascade. The first step of Ras-dependent activation of ERK signaling is Ras binding to members of the Raf family of MAP kinase kinase kinases, C-Raf and B-Raf. Recently, it has been reported thatin melanoma cells harboring oncogenic Ras mutations, B-Raf does not bind to Ras and does not contribute to basal ERK activation. For other types of Ras-mutant tumors, the relative contributions of C-Raf and B-Raf are not known. We examined non-melanoma cancer cell lines containing oncogenic Ras mutations and express both C-Raf and B-Raf isoforms, including the lung cancer cell line H1299 cells. Both B-Raf and C-Raf were constitutively bound to oncogenic Ras and contributedtoRas-dependent ERK activation. Ras bindingto B-Raf and C-Raf were both subject to inhibition by the cAMP-dependent protein kinase PKA. cAMP inhibited the growth of H1299 cells and Ras-dependent ERK activation via PKA. PKA inhibited the binding of Ras to both C-Raf and B-Raf through phosphorylations of C-Raf at Ser-259 and B-Raf at Ser-365, respectively. These studies demonstrate thatinnon-melanocytic Ras-mutant cancer cells, Ras signalingtoB-Rafis a significant contributor to ERK activation and that the B-Raf pathway, like that of C-Raf, is a target for inhibition by PKA. We suggest that cAMP and hormones coupled to cAMP may prove useful in dampening the effects of oncogenic Ras in non-melanocytic cancer cells through PKA-dependent actions on B-Raf as well as C-Raf.

UR - http://www.scopus.com/inward/record.url?scp=84884561095&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84884561095&partnerID=8YFLogxK

U2 - 10.1074/jbc.M113.463067

DO - 10.1074/jbc.M113.463067

M3 - Article

C2 - 23893412

AN - SCOPUS:84884561095

VL - 288

SP - 27646

EP - 27657

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 38

ER -