PMID- 8617784
OWN - NLM
STAT- MEDLINE
DCOM- 19960611
LR  - 20210210
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 271
IP  - 9
DP  - 1996 Mar 1
TI  - Identification of determinants in the alpha-subunit of Gq required for 
      phospholipase C activation.
PG  - 5066-72
AB  - A series of chimeras between a constitutively active mutant of the alpha-subunit 
      of Gq and the alpha-subunit of Gs was constructed to identify the domains in 
      alphaq specifically involved in interaction with its effector phosphoinositide 
      phospholipase C (PLC). Transient expression of the chimeric proteins and 
      measurement of the production of inositol phosphates and cAMP in HEK-293 cells 
      revealed that the Ile217-Lys276 sequence of alphaq contained the PLC interaction 
      sites, whereas the residues for activation of adenylyl cyclase were in the 
      Ile235-Leu294 sequence of alphas. Alanine scanning mutagenesis of the 
      Ile217-Lys276 region of alphaq further identified two clusters of amino acids 
      (Asp243,Asn244,Glu245 and Arg256,Thr257) that were specifically required for 
      interaction with PLC. Comparison of the sequences of alphaq, alphas, and alphat 
      showed that the PLC-interacting residues identified in alphaq are different from 
      the corresponding residues in alphas and alphat that are involved in effector 
      activation. Alignment of the sequences of alphaq and alphat, based on the crystal 
      structure of alphat (Noel, J. P., Hamm, H. E., and Sigler, P. D. (1993) Nature 
      366, 654-663), indicated that the PLC-activating residues of alphaq are located 
      in alpha-helix 3 and its linker to beta-sheet 4, which are adjacent to a switch 
      region whose conformation changes with activation. It is proposed that the 
      selectivity of alphaq for PLC involves relatively few amino acids, but that the 
      effector may interact with other nonselective sequences in the alpha-subunit.
FAU - Venkatakrishnan, G
AU  - Venkatakrishnan G
AD  - Howard Hughes Medical Institute and the Department of Molecular Physiology and 
      Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 
      37232-0295, USA.
FAU - Exton, J H
AU  - Exton JH
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (DNA Primers)
RN  - 0 (Inositol Phosphates)
RN  - 0 (Macromolecular Substances)
RN  - 0 (Peptide Fragments)
RN  - 0 (Recombinant Fusion Proteins)
RN  - EC 3.1.4.- (Phosphoric Diester Hydrolases)
RN  - EC 3.4.21.4 (Trypsin)
RN  - EC 3.6.1.- (GTP-Binding Proteins)
RN  - EC 4.6.1.13 (Phosphatidylinositol Diacylglycerol-Lyase)
RN  - OF5P57N2ZX (Alanine)
SB  - IM
MH  - Alanine
MH  - Amino Acid Sequence
MH  - Base Sequence
MH  - Binding Sites
MH  - Cell Line
MH  - DNA Primers
MH  - Enzyme Activation
MH  - GTP-Binding Proteins/*chemistry/*metabolism
MH  - Humans
MH  - Inositol Phosphates/metabolism
MH  - Kidney
MH  - Macromolecular Substances
MH  - Molecular Sequence Data
MH  - Mutagenesis, Site-Directed
MH  - Peptide Fragments/chemistry/isolation & purification
MH  - Phosphatidylinositol Diacylglycerol-Lyase
MH  - Phosphoric Diester Hydrolases/*metabolism
MH  - Polymerase Chain Reaction
MH  - Protein Conformation
MH  - Protein Structure, Secondary
MH  - Recombinant Fusion Proteins/chemistry/metabolism
MH  - Second Messenger Systems
MH  - Sequence Homology, Amino Acid
MH  - Transfection
MH  - Trypsin
EDAT- 1996/03/01 00:00
MHDA- 1996/03/01 00:01
CRDT- 1996/03/01 00:00
PHST- 1996/03/01 00:00 [pubmed]
PHST- 1996/03/01 00:01 [medline]
PHST- 1996/03/01 00:00 [entrez]
AID - S0021-9258(18)82551-0 [pii]
AID - 10.1074/jbc.271.9.5066 [doi]
PST - ppublish
SO  - J Biol Chem. 1996 Mar 1;271(9):5066-72. doi: 10.1074/jbc.271.9.5066.