PMID- 12138085
OWN - NLM
STAT- MEDLINE
DCOM- 20021113
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 277
IP  - 39
DP  - 2002 Sep 27
TI  - Carbonic anhydrase II binds to and enhances activity of the Na+/H+ exchanger.
PG  - 36085-91
AB  - We examined the ability of carbonic anhydrase II to bind to and affect the 
      transport efficiency of the NHE1 isoform of the mammalian Na(+)/H(+) exchanger. 
      The C-terminal region of NHE1 was expressed in Escherichia coli fused with an 
      N-terminal glutathionine S-transferase or with a C-terminal polyhistidine tag. 
      Using a microtiter plate binding assay we showed that the C-terminal region of 
      NHE1 binds carbonic anhydrase II (CAII) and binding was stimulated by low pH and 
      blocked by antibodies against the C-terminal of NHE1. The binding to NHE1 was 
      confirmed by demonstrating protein-protein interaction using affinity blotting 
      with CAII and immobilized NHE1 fusion proteins. CAII co-immunoprecipitated with 
      NHE1 from CHO cells suggesting the proteins form a complex in vivo. In cells 
      expressing CAII and NHE1, the H(+) transport rate was almost 2-fold greater than 
      in cells expressing NHE1 alone. The CAII inhibitor acetazolamide significantly 
      decreased the H(+) transport rate of NHE1 and transfection with a dominant 
      negative CAII inhibited NHE1 activity. Phosphorylation of the C-terminal of NHE1 
      greatly increased the binding of CAII. Our study suggests that NHE1 transport 
      efficiency is influenced by CAII, likely through a direct interaction at the 
      C-terminal region. Regulation of NHE1 activity by phosphorylation could involve 
      modulation of CAII binding.
FAU - Li, Xiuju
AU  - Li X
AD  - Department of Biochemistry and Physiology, Canadian Institute of Health Research 
      Membrane Protein Group, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
FAU - Alvarez, Bernardo
AU  - Alvarez B
FAU - Casey, Joseph R
AU  - Casey JR
FAU - Reithmeier, Reinhart A F
AU  - Reithmeier RA
FAU - Fliegel, Larry
AU  - Fliegel L
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20020722
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Recombinant Fusion Proteins)
RN  - 0 (Sodium-Hydrogen Exchangers)
RN  - 4QD397987E (Histidine)
RN  - EC 4.2.1.- (Carbonic Anhydrase II)
SB  - IM
MH  - Animals
MH  - Binding Sites
MH  - Blotting, Western
MH  - CHO Cells
MH  - Carbonic Anhydrase II/*chemistry/*metabolism
MH  - Cricetinae
MH  - Dose-Response Relationship, Drug
MH  - Electrophoresis, Polyacrylamide Gel
MH  - Histidine/chemistry
MH  - Hydrogen-Ion Concentration
MH  - Phosphorylation
MH  - Precipitin Tests
MH  - Protein Binding
MH  - Protein Structure, Tertiary
MH  - Recombinant Fusion Proteins/metabolism
MH  - Sodium-Hydrogen Exchangers/*metabolism
MH  - Time Factors
MH  - Transfection
EDAT- 2002/07/26 10:00
MHDA- 2002/11/26 04:00
CRDT- 2002/07/26 10:00
PHST- 2002/07/26 10:00 [pubmed]
PHST- 2002/11/26 04:00 [medline]
PHST- 2002/07/26 10:00 [entrez]
AID - S0021-9258(18)36575-X [pii]
AID - 10.1074/jbc.M111952200 [doi]
PST - ppublish
SO  - J Biol Chem. 2002 Sep 27;277(39):36085-91. doi: 10.1074/jbc.M111952200. Epub 2002 
      Jul 22.