G-proteins in guinea pig airway smooth muscle

Identification and functional involvement

Sharmishtha Joshi, Worku Abebe, Devendra K. Agrawal

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In airway smooth muscle, G-proteins have not been identified directly as yet. This study was an attempt to detect various types of conventional G(i)- and G(s)-proteins in purified membranes of guinea pig airway smooth muscle and to assess the involvement of the G-proteins in agonist-induced contractile response of the smooth muscle. Immunoblotting using AS/7 antibody which recognizes G(i-1/2) demonstrated the presence of polypeptides of M(r) 34, 41 and 75 kDa, Polypeptides of M(r) 43, 46 and 48 kDa were identified with RM/1 antibody that detects G(s)-type G-proteins. The AG/1 antibody that recognizes α-subunits common to all G(i)- and G(s) proteins detected two polypeptides of M(r) 41 and 75 kDa. Heterotrimeric structure of the G-proteins was confirmed by the identification of a single dense β-subunit band at M(r) 39 kDa with SW/1 antibody. Pertussis toxin (PT) ADP-ribosylated three G(i)α polypeptides of M(r) 41, 43, and 62 kDa, On the other hand, cholera toxin (CT) catalysed the ADP-ribosylation of two G(s)α polypeptides of M(r) 46 and 62 kDa. Both PT and CT attenuated the maximum contractile responses of the airway smooth muscle to the muscarinic agonist, methacholine. Pretreatment of the tissues with the sulphydryl alkylating G-protein inhibitor, N-ethylmaleimide, also inhibited the maximum contractions to methacholine. These data suggest that plasma membranes of guinea pig airway smooth muscle contain a variety of conventional, including G(s) and G(i), and other types of G-proteins, and at least a portion of the proteins present may be involved in mediating the contractile responses of the smooth muscle to an agonist such as methacholine.

Original languageEnglish (US)
Pages (from-to)195-202
Number of pages8
JournalPharmacological Research
Volume33
Issue number3
DOIs
StatePublished - Jan 1 1996
Externally publishedYes

Fingerprint

GTP-Binding Proteins
Smooth Muscle
Guinea Pigs
Methacholine Chloride
Peptides
Antibodies
Cholera Toxin
Pertussis Toxin
Adenosine Diphosphate
Heterotrimeric GTP-Binding Proteins
Muscarinic Agonists
Proteins
Ethylmaleimide
Muscle Proteins
Immunoblotting
Cell Membrane
Membranes

Keywords

  • ADP-ribosylation
  • Bacterial toxins
  • G-proteins
  • Guinea pig trachealis
  • Immunoblotting

ASJC Scopus subject areas

  • Pharmacology

Cite this

G-proteins in guinea pig airway smooth muscle : Identification and functional involvement. / Joshi, Sharmishtha; Abebe, Worku; Agrawal, Devendra K.

In: Pharmacological Research, Vol. 33, No. 3, 01.01.1996, p. 195-202.

Research output: Contribution to journalArticle

Joshi, Sharmishtha ; Abebe, Worku ; Agrawal, Devendra K. / G-proteins in guinea pig airway smooth muscle : Identification and functional involvement. In: Pharmacological Research. 1996 ; Vol. 33, No. 3. pp. 195-202.
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