PMID- 10191253
OWN - NLM
STAT- MEDLINE
DCOM- 19990623
LR  - 20181113
IS  - 0264-6021 (Print)
IS  - 0264-6021 (Linking)
VI  - 339 ( Pt 2)
DP  - 1999 Apr 15
TI  - Methylated C-terminal leucine residue of PP2A catalytic subunit is important for 
      binding of regulatory Balpha subunit.
PG  - 241-6
AB  - Methylation of the C-terminal leucine residue (Leu309) of protein
      serine/threonine phosphatase 2A catalytic subunit (PP2AC) is known to regulate
      catalytic activity in vitro, but the functional consequence(s) of this
      post-translational modification in the context of the cell remain unclear.
      Alkali-induced demethylation of PP2AC in purified PP2A heterotrimer (ABalphaC),
      but not in purified PP2A heterodimer (AC), indicated that a larger fraction of
      PP2AC is carboxymethylated in ABalphaC than in AC. To explore the role of Leu309 
      in PP2A holoenzyme assembly, epitope-tagged PP2A catalytic subunit (HA-PP2A) and 
      a mutant of HA-PP2A containing an alanine residue in place of Leu309
      (HA-PP2A-L309A) were transiently expressed in COS cells. Both recombinant
      proteins exhibited serine/threonine phosphatase activity when immunoisolated from
      COS cell extracts. HA-PP2A, but not HA-PP2A-L309A, was carboxymethylated in
      vitro. A chromatographic analysis of cell extracts indicated that most endogenous
      PP2AC and HA-PP2A were co-eluted with the A and Balpha regulatory subunits of
      PP2A, whereas most HA-PP2A-L309A seemed to elute with the A subunit as a smaller 
      complex or, alternatively, as free catalytic (C) subunit. The A subunit
      co-immunoisolated with both tagged proteins; however, substantially less Balpha
      subunit co-immunoisolated with HA-PP2A-L309A than with HA-PP2A. These results
      demonstrate that the reversibly methylated C-terminal leucine residue of PP2AC is
      important for Balpha regulatory subunit binding. Furthermore, the results provide
      evidence for an interrelationship between PP2AC carboxymethylation and PP2A
      holoenzyme assembly.
FAU - Bryant, J C
AU  - Bryant JC
AD  - Department of Pharmacology, Room 424 MRB1, Vanderbilt University Medical Center, 
      Nashville, TN 37232-6600, USA.
FAU - Westphal, R S
AU  - Westphal RS
FAU - Wadzinski, B E
AU  - Wadzinski BE
LA  - eng
GR  - CA68485/CA/NCI NIH HHS/United States
GR  - DK20593/DK/NIDDK NIH HHS/United States
GR  - GM51366/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Biochem J
JT  - The Biochemical journal
JID - 2984726R
RN  - 0 (DNA Primers)
RN  - EC 3.1.3.16 (Phosphoprotein Phosphatases)
RN  - EC 3.1.3.16 (Protein Phosphatase 2)
RN  - GMW67QNF9C (Leucine)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Base Sequence
MH  - COS Cells
MH  - Catalytic Domain
MH  - DNA Primers
MH  - Leucine/metabolism
MH  - Methylation
MH  - Mutagenesis, Site-Directed
MH  - Phosphoprotein Phosphatases/chemistry/genetics/*metabolism
MH  - Protein Binding
MH  - Protein Phosphatase 2
PMC - PMC1220151
EDAT- 1999/04/07 00:00
MHDA- 1999/04/07 00:01
CRDT- 1999/04/07 00:00
PHST- 1999/04/07 00:00 [pubmed]
PHST- 1999/04/07 00:01 [medline]
PHST- 1999/04/07 00:00 [entrez]
PST - ppublish
SO  - Biochem J. 1999 Apr 15;339 ( Pt 2):241-6.