Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits

Sang Bong Lee, Seok Hwan Shin, John R. Hepler, Alfred G. Gilman, Sue Goo Rhee

Research output: Contribution to journalArticle

112 Citations (Scopus)

Abstract

The β- but not the γ- and δ-type isozymes of inositol phospholipid-specific phospholipase C (PLC) are activated by G protein αq and βγ subunits. The β-type PLC isozymes differ from other isozymes in that they contain a long carboxyl-terminal region downstream of the Y catalytic domain and a region rich in acidic amino acids between the two separated X and Y catalytic domains. To determine the sites on PLC-β2 that participate in the interaction of the enzyme with αq and βγ subunits, we introduced specific truncations and substitutions in the PLC-β2 cDNA at positions corresponding to the carboxyl-terminal and acidic amino acidrich regions, respectively. After transient expression of these cDNA clones in CV-1 cells, the mutant enzymes were partially purified and their capacity to be activated by αq and βγ subunits determined. Substitution of glutamine residues for three or all seven of a stretch of consecutive glutamic acids in the acidic domain of PLC-β2 affected neither αq- nor βγ-dependent activation significantly. Carboxyl-terminal truncation to residue Gly-934 or to residue Ala-867 resulted in enzymes that were activated by βγ but not by αq. This result suggests that the carboxyl-terminal region of PLC-β2 is required for activation by αq, and that βγ subunits interact with a different region of the enzyme. Thus, αq and βγ subunits may independently modulate a single PLC-β2 molecule concurrently.

Original languageEnglish (US)
Pages (from-to)25952-25957
Number of pages6
JournalJournal of Biological Chemistry
Volume268
Issue number34
StatePublished - Dec 5 1993

Fingerprint

Protein Subunits
Type C Phospholipases
Mutant Proteins
GTP-Binding Proteins
Chemical activation
Isoenzymes
Enzymes
Catalytic Domain
Substitution reactions
Complementary DNA
Glutamates
Acidic Amino Acids
Phosphatidylinositols
Glutamine
Clone Cells
Molecules

ASJC Scopus subject areas

  • Biochemistry

Cite this

Lee, S. B., Shin, S. H., Hepler, J. R., Gilman, A. G., & Rhee, S. G. (1993). Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits. Journal of Biological Chemistry, 268(34), 25952-25957.

Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits. / Lee, Sang Bong; Shin, Seok Hwan; Hepler, John R.; Gilman, Alfred G.; Rhee, Sue Goo.

In: Journal of Biological Chemistry, Vol. 268, No. 34, 05.12.1993, p. 25952-25957.

Research output: Contribution to journalArticle

Lee, SB, Shin, SH, Hepler, JR, Gilman, AG & Rhee, SG 1993, 'Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits', Journal of Biological Chemistry, vol. 268, no. 34, pp. 25952-25957.
Lee SB, Shin SH, Hepler JR, Gilman AG, Rhee SG. Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits. Journal of Biological Chemistry. 1993 Dec 5;268(34):25952-25957.
Lee, Sang Bong ; Shin, Seok Hwan ; Hepler, John R. ; Gilman, Alfred G. ; Rhee, Sue Goo. / Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits. In: Journal of Biological Chemistry. 1993 ; Vol. 268, No. 34. pp. 25952-25957.
@article{f716de1c8f284f5a801d67289ee0d6f4,
title = "Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits",
abstract = "The β- but not the γ- and δ-type isozymes of inositol phospholipid-specific phospholipase C (PLC) are activated by G protein αq and βγ subunits. The β-type PLC isozymes differ from other isozymes in that they contain a long carboxyl-terminal region downstream of the Y catalytic domain and a region rich in acidic amino acids between the two separated X and Y catalytic domains. To determine the sites on PLC-β2 that participate in the interaction of the enzyme with αq and βγ subunits, we introduced specific truncations and substitutions in the PLC-β2 cDNA at positions corresponding to the carboxyl-terminal and acidic amino acidrich regions, respectively. After transient expression of these cDNA clones in CV-1 cells, the mutant enzymes were partially purified and their capacity to be activated by αq and βγ subunits determined. Substitution of glutamine residues for three or all seven of a stretch of consecutive glutamic acids in the acidic domain of PLC-β2 affected neither αq- nor βγ-dependent activation significantly. Carboxyl-terminal truncation to residue Gly-934 or to residue Ala-867 resulted in enzymes that were activated by βγ but not by αq. This result suggests that the carboxyl-terminal region of PLC-β2 is required for activation by αq, and that βγ subunits interact with a different region of the enzyme. Thus, αq and βγ subunits may independently modulate a single PLC-β2 molecule concurrently.",
author = "Lee, {Sang Bong} and Shin, {Seok Hwan} and Hepler, {John R.} and Gilman, {Alfred G.} and Rhee, {Sue Goo}",
year = "1993",
month = "12",
day = "5",
language = "English (US)",
volume = "268",
pages = "25952--25957",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "34",

}

TY - JOUR

T1 - Activation of phospholipase C-β2 mutants by G protein αq and βγ subunits

AU - Lee, Sang Bong

AU - Shin, Seok Hwan

AU - Hepler, John R.

AU - Gilman, Alfred G.

AU - Rhee, Sue Goo

PY - 1993/12/5

Y1 - 1993/12/5

N2 - The β- but not the γ- and δ-type isozymes of inositol phospholipid-specific phospholipase C (PLC) are activated by G protein αq and βγ subunits. The β-type PLC isozymes differ from other isozymes in that they contain a long carboxyl-terminal region downstream of the Y catalytic domain and a region rich in acidic amino acids between the two separated X and Y catalytic domains. To determine the sites on PLC-β2 that participate in the interaction of the enzyme with αq and βγ subunits, we introduced specific truncations and substitutions in the PLC-β2 cDNA at positions corresponding to the carboxyl-terminal and acidic amino acidrich regions, respectively. After transient expression of these cDNA clones in CV-1 cells, the mutant enzymes were partially purified and their capacity to be activated by αq and βγ subunits determined. Substitution of glutamine residues for three or all seven of a stretch of consecutive glutamic acids in the acidic domain of PLC-β2 affected neither αq- nor βγ-dependent activation significantly. Carboxyl-terminal truncation to residue Gly-934 or to residue Ala-867 resulted in enzymes that were activated by βγ but not by αq. This result suggests that the carboxyl-terminal region of PLC-β2 is required for activation by αq, and that βγ subunits interact with a different region of the enzyme. Thus, αq and βγ subunits may independently modulate a single PLC-β2 molecule concurrently.

AB - The β- but not the γ- and δ-type isozymes of inositol phospholipid-specific phospholipase C (PLC) are activated by G protein αq and βγ subunits. The β-type PLC isozymes differ from other isozymes in that they contain a long carboxyl-terminal region downstream of the Y catalytic domain and a region rich in acidic amino acids between the two separated X and Y catalytic domains. To determine the sites on PLC-β2 that participate in the interaction of the enzyme with αq and βγ subunits, we introduced specific truncations and substitutions in the PLC-β2 cDNA at positions corresponding to the carboxyl-terminal and acidic amino acidrich regions, respectively. After transient expression of these cDNA clones in CV-1 cells, the mutant enzymes were partially purified and their capacity to be activated by αq and βγ subunits determined. Substitution of glutamine residues for three or all seven of a stretch of consecutive glutamic acids in the acidic domain of PLC-β2 affected neither αq- nor βγ-dependent activation significantly. Carboxyl-terminal truncation to residue Gly-934 or to residue Ala-867 resulted in enzymes that were activated by βγ but not by αq. This result suggests that the carboxyl-terminal region of PLC-β2 is required for activation by αq, and that βγ subunits interact with a different region of the enzyme. Thus, αq and βγ subunits may independently modulate a single PLC-β2 molecule concurrently.

UR - http://www.scopus.com/inward/record.url?scp=0027132929&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027132929&partnerID=8YFLogxK

M3 - Article

VL - 268

SP - 25952

EP - 25957

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 34

ER -