PMID- 10648842
OWN - NLM
STAT- MEDLINE
DCOM- 20000222
LR  - 20211203
IS  - 0014-5793 (Print)
IS  - 0014-5793 (Linking)
VI  - 466
IP  - 1
DP  - 2000 Jan 21
TI  - Hepatic epidermal growth factor-regulated mitogen-activated protein kinase kinase
      kinase activity in the rat: lack of identity with known forms of raf and MEKK.
PG  - 200-4
AB  - Mitogenic signaling involves protein kinases that phosphorylate the
      mitogen-activated protein kinase (MAPK) activator, MEK. In rats, basal hepatic
      MEK kinase activity is low in vivo in both adult rats and late gestation fetal
      rats, and is markedly stimulated by intraperitoneal administration of epidermal
      growth factor (EGF). The level of stimulated MEK phosphorylating activity is
      approximately 15 times higher in fetal liver than in adult liver. To identify
      regulated forms of the two categories of MEK kinase, Raf and MEKK, Western
      immunoblotting, immunoprecipitation kinase assays and immunodepletion studies
      were performed. Western immunoblotting confirmed that Raf-1, A-Raf, B-Raf, MEKK1 
      and MEKK2 were present at similar levels in E19 and adult liver. However,
      specific immunoprecipitation kinase assays did not detect any kinases that could 
      account for marked EGF sensitivity or the higher level of activity in E19
      fetuses. Immunodepletion studies produced a marked reduction in immunoreactive
      Raf/MEKK content and activity, but a minimal decrease in the ability of
      chromatography fractions to phosphorylate and activate recombinant MEK-1. Our
      results indicate that hepatic, EGF-sensitive MEK kinase activity may reside with 
      a previously unidentified and physiologically relevant form of Raf and/or MEKK.
FAU - Gruppuso, P A
AU  - Gruppuso PA
AD  - Department of Pediatrics, Rhode Island Hospital and Brown University, 593 Eddy
      Street, Providence, RI, USA. philip_gruppuso@brown.edu
FAU - Boylan, J M
AU  - Boylan JM
LA  - eng
GR  - HD11343/HD/NICHD NIH HHS/United States
GR  - HD24455/HD/NICHD NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - FEBS Lett
JT  - FEBS letters
JID - 0155157
RN  - 62229-50-9 (Epidermal Growth Factor)
RN  - EC 2.7.11.1 (Protein Serine-Threonine Kinases)
RN  - EC 2.7.11.1 (Proto-Oncogene Proteins c-raf)
RN  - EC 2.7.11.25 (MAP Kinase Kinase Kinase 1)
RN  - EC 2.7.11.25 (MAP Kinase Kinase Kinase 2)
RN  - EC 2.7.11.25 (MAP Kinase Kinase Kinases)
RN  - EC 2.7.11.25 (MAP3K1 protein, human)
RN  - EC 2.7.11.25 (MAP3K2 protein, human)
SB  - IM
MH  - Animals
MH  - Epidermal Growth Factor/*pharmacology
MH  - Female
MH  - Fetus/enzymology
MH  - Humans
MH  - Liver/*enzymology
MH  - *MAP Kinase Kinase Kinase 1
MH  - MAP Kinase Kinase Kinase 2
MH  - MAP Kinase Kinase Kinases/isolation & purification/*metabolism
MH  - Pregnancy
MH  - *Protein Serine-Threonine Kinases
MH  - Proto-Oncogene Proteins c-raf/isolation & purification/*metabolism
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Signal Transduction
EDAT- 2000/01/29 09:00
MHDA- 2000/02/26 09:00
CRDT- 2000/01/29 09:00
PHST- 2000/01/29 09:00 [pubmed]
PHST- 2000/02/26 09:00 [medline]
PHST- 2000/01/29 09:00 [entrez]
AID - S0014-5793(99)01792-5 [pii]
AID - 10.1016/s0014-5793(99)01792-5 [doi]
PST - ppublish
SO  - FEBS Lett. 2000 Jan 21;466(1):200-4. doi: 10.1016/s0014-5793(99)01792-5.