PMID- 10620507
OWN - NLM
STAT- MEDLINE
DCOM- 20000302
LR  - 20190501
IS  - 0264-6021 (Print)
IS  - 0264-6021 (Linking)
VI  - 345 Pt 2
DP  - 2000 Jan 15
TI  - 14-3-3 isotypes facilitate coupling of protein kinase C-zeta to Raf-1: negative
      regulation by 14-3-3 phosphorylation.
PG  - 297-306
AB  - 14-3-3 Proteins may function as adapters or scaffold in signal-transduction
      pathways. We found previously that protein kinase C-zeta (PKC-zeta) can
      phosphorylate and activate Raf-1 in a signalling complex [van Dijk, Hilkmann and 
      van Blitterswijk (1997) Biochem. J. 325, 303-307]. We report now that
      PKC-zeta-Raf-1 interaction is mediated by 14-3-3 proteins in vitro and in vivo.
      Co-immunoprecipitation experiments in COS cells revealed that complex formation
      between PKC-zeta and Raf-1 is mediated strongly by the 14-3-3beta and -theta;
      isotypes, but not by 14-3-3zeta. Far-Western blotting revealed that 14-3-3 binds 
      PKC-zeta directly at its regulatory domain, where a S186A mutation in a putative 
      14-3-3-binding domain strongly reduced the binding and the complex formation with
      14-3-3beta and Raf-1. Treatment of PKC-zeta with lambda protein phosphatase also 
      reduced its binding to 14-3-3beta in vitro. Preincubation of an immobilized Raf-1
      construct with 14-3-3beta facilitated PKC-zeta binding. Together, the results
      suggest that 14-3-3 binds both PKC-zeta (at phospho-Ser-186) and Raf-1 in a
      ternary complex. Complex formation was much stronger with a kinase-inactive
      PKC-zeta mutant than with wild-type PKC-zeta, supporting the idea that kinase
      activity leads to complex dissociation. 14-3-3beta and -θ were substrates
      for PKC-zeta, whereas 14-3-3zeta was not. Phosphorylation of 14-3-3beta by
      PKC-zeta negatively regulated their physical association. 14-3-3beta with its
      putative PKC-zeta phosphorylation sites mutated enhanced co-precipitation between
      PKC-zeta and Raf-1, suggesting that phosphorylation of 14-3-3 by PKC-zeta weakens
      the complex in vivo. We conclude that 14-3-3 facilitates coupling of PKC-zeta to 
      Raf-1 in an isotype-specific and phosphorylation-dependent manner. We suggest
      that 14-3-3 is a transient mediator of Raf-1 phosphorylation and activation by
      PKC-zeta.
FAU - Van Der Hoeven, P C
AU  - Van Der Hoeven PC
AD  - Division of Cellular Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 
      121, 1066 CX Amsterdam, The Netherlands.
FAU - Van Der Wal, J C
AU  - Van Der Wal JC
FAU - Ruurs, P
AU  - Ruurs P
FAU - Van Dijk, M C
AU  - Van Dijk MC
FAU - Van Blitterswijk, J
AU  - Van Blitterswijk J
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Biochem J
JT  - The Biochemical journal
JID - 2984726R
RN  - 0 (14-3-3 Proteins)
RN  - 0 (Protein Isoforms)
RN  - 0 (Proteins)
RN  - 0 (Recombinant Proteins)
RN  - 17885-08-4 (Phosphoserine)
RN  - EC 1.14.16.2 (Tyrosine 3-Monooxygenase)
RN  - EC 2.7.11.1 (Proto-Oncogene Proteins c-raf)
RN  - EC 2.7.11.1 (protein kinase C zeta)
RN  - EC 2.7.11.13 (Protein Kinase C)
SB  - IM
MH  - 14-3-3 Proteins
MH  - Phosphorylation
MH  - Phosphoserine/metabolism
MH  - Protein Binding
MH  - Protein Isoforms/genetics/metabolism
MH  - Protein Kinase C/*metabolism
MH  - Protein Structure, Quaternary
MH  - Proteins/genetics/*metabolism
MH  - Proto-Oncogene Proteins c-raf/*metabolism
MH  - Recombinant Proteins/metabolism
MH  - Signal Transduction
MH  - Substrate Specificity
MH  - *Tyrosine 3-Monooxygenase
PMC - PMC1220759
EDAT- 2000/01/06 09:00
MHDA- 2000/03/04 09:00
CRDT- 2000/01/06 09:00
PHST- 2000/01/06 09:00 [pubmed]
PHST- 2000/03/04 09:00 [medline]
PHST- 2000/01/06 09:00 [entrez]
AID - 10.1042/0264-6021:3450297 [doi]
PST - ppublish
SO  - Biochem J. 2000 Jan 15;345 Pt 2:297-306. doi: 10.1042/0264-6021:3450297.