Plant Physiol, April 2003, Vol. 131, pp. 1718-1726
Ethylene Rapidly Up-Regulates the Activities of Both Monomeric
GTP-Binding Proteins and Protein Kinase(s) in Epicotyls of
Pea1
Igor E.
Moshkov,
Galina V.
Novikova,
Luis A.J.
Mur,
Aileen R.
Smith, and
Michael A.
Hall*
Timiryazev Institute of Plant Physiology RAS, Botanicheskaya 35, Moscow 127276, Russia (I.E.M., G.V.N.); and Institute of Biological
Sciences, University of Wales, Aberystwyth SY23 3DA, United Kingdom
(L.A.J.M., A.R.S., M.A.H.)
It is demonstrated that, in etiolated pea (Pisum
sativum) epicotyls, ethylene affects the activation of both
monomeric GTP-binding proteins (monomeric G-proteins) and protein
kinases. For monomeric G-proteins, the effect may be a rapid (2 min)
and bimodal up-regulation, a transiently unimodal activation, or a
transient down-regulation. Pretreatment with 1-methylcyclopropene
abolishes the response to ethylene overall. Immunoprecipitation studies
indicate that some of the monomeric G-proteins affected may be of the
Rab class. Protein kinase activity is rapidly up-regulated by ethylene,
the effect is inhibited by 1-methylcyclopropene, and the activation is
bimodal. Immunoprecipitation indicates that the kinase(s) are of the
MAP kinase ERK1 group. It is proposed that the data support the
hypothesis that a transduction chain exists that is separate and
antagonistic to that currently revealed by studies on Arabidopsis mutants.
1
This work was supported in part by INTAS
(grant no. 99-01200) and by the Russian Foundation for Basic Research
(grant no. 02-04-48414).
*
Corresponding author; e-mail mzh{at}aber.ac.uk; fax
44-1970-622307.
© 2003 American Society of Plant Biologists
