PMID- 10542238
OWN - NLM
STAT- MEDLINE
DCOM- 19991213
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 45
DP  - 1999 Nov 5
TI  - Role of the first extracellular loop in the functional activation of CCR2. The 
      first extracellular loop contains distinct domains necessary for both agonist 
      binding and transmembrane signaling.
PG  - 32055-62
AB  - The physiological cellular responses to monocyte chemoattractant protein-1 
      (MCP-1), a potent chemotactic and activating factor for mononuclear leukocytes, 
      are mediated by specific binding to CCR2. The aim of this investigation is to 
      identify receptor microdomains that are involved in high affinity agonist binding 
      and receptor activation. The results from our functional studies in which we 
      utilized neutralizing antisera against CCR2 are consistent with a multidomain 
      binding model, previously proposed by others. The first extracellular loop was of 
      particular interest, because in addition to a ligand-binding domain it contained 
      also information for receptor activation, crucial for transmembrane signaling. 
      Replacement of the first extracellular loop of CCR2 with the corresponding region 
      of CCR1 decreased the MCP-1 binding affinity about 10-fold and prevented 
      transmembrane signaling. A more detailed analysis by site-directed mutagenesis 
      revealed that this receptor segment contains two distinct microdomains. The amino 
      acid residues Asn(104) and Glu(105) are essential for high affinity agonist 
      binding but are not involved in receptor activation. In contrast, the charged 
      amino acid residue His(100) does not contribute to ligand binding but is vital 
      for receptor activation and initiation of transmembrane signaling. We hypothesize 
      that the interaction of agonist with this residue initiates the conformational 
      switch that allows the formation of the functional CCR2-G protein complex.
FAU - Han, K H
AU  - Han KH
AD  - Department of Medicine, University of California, San Diego, La Jolla, California 
      92093-0682, USA.
FAU - Green, S R
AU  - Green SR
FAU - Tangirala, R K
AU  - Tangirala RK
FAU - Tanaka, S
AU  - Tanaka S
FAU - Quehenberger, O
AU  - Quehenberger O
LA  - eng
GR  - AI41719-01A1/AI/NIAID NIH HHS/United States
GR  - HL56989-01/HL/NHLBI 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  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (CCR2 protein, human)
RN  - 0 (Chemokine CCL2)
RN  - 0 (Ligands)
RN  - 0 (Receptors, CCR2)
RN  - 0 (Receptors, Chemokine)
RN  - 37589-80-3 (Guanosine 5'-O-(3-Thiotriphosphate))
RN  - EC 3.6.1.- (GTP-Binding Proteins)
SB  - IM
MH  - Amino Acid Sequence
MH  - Binding Sites
MH  - Cell Line
MH  - Chemokine CCL2/*metabolism
MH  - GTP-Binding Proteins/metabolism
MH  - Guanosine 5'-O-(3-Thiotriphosphate)/metabolism
MH  - Humans
MH  - Ligands
MH  - Molecular Sequence Data
MH  - Protein Conformation
MH  - Receptors, CCR2
MH  - Receptors, Chemokine/*metabolism
MH  - *Signal Transduction
EDAT- 1999/11/05 00:00
MHDA- 1999/11/05 00:01
CRDT- 1999/11/05 00:00
PHST- 1999/11/05 00:00 [pubmed]
PHST- 1999/11/05 00:01 [medline]
PHST- 1999/11/05 00:00 [entrez]
AID - S0021-9258(19)51526-5 [pii]
AID - 10.1074/jbc.274.45.32055 [doi]
PST - ppublish
SO  - J Biol Chem. 1999 Nov 5;274(45):32055-62. doi: 10.1074/jbc.274.45.32055.