ISSN:
1432-2048
Keywords:
Ethylene
;
Guanosine
;
5′-triphosphate binding
;
Guanosine 5′-triphosphate-binding proteins (small)
;
Membrane (GTP binding)
;
Pisum
;
Signal transduction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Binding of [35S]guanosine 5′-o-(3-thiotriphosphate) (GTPγS) and of [α-32P]guanosine triphosphate ([α-32P]GTP) has been demonstrated in membrane preparations from epicotyl tips of etiolated plants ofPisum sativum L.; binding has also been shown in KCl-and Triton X-100-solubilised fractions from these membranes. Binding of GTPγS was of high affinity (K D = 3.17 × 10−8M), showed high specificity for guanine nucleotides and was stimulated by Mg2+ in the micromolar range. Binding was associated with only low levels of guanosine 5′-triphosphatase activity and was unaffected by treatment with mastoparan. In-vivo application of ethylene at 1 μl·l−1 stimulated GTP binding in fractions released from membranes by treatment with 750 mM KCl and Triton X-100. Affinity probing with ([α-32P]GTP) showed pronounced specific GTP binding to polypeptide(s) with relative molecular mass (Mr) of 28 kDa. The binding was stimulated markedly by ethylene and to some extent by AIF4 −. Mouse monoclonal anti-pan-ras antibodies cross-reacted with several polypeptides in the 20 to 30-kDa region, and an [α-32P]GTP-labelled protein of Mr 28 kDa was precipitated by the same antibodies. The data indicate that the transduction of the ethylene signal may involve the intervention of GTP-binding proteins similar to the small monomeric GTP-binding proteins.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01258674
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