PubMed Journals: J Biol Chem
Source: PMID: 12235136
⇦ ⇨ J Biol Chem. 2002 Nov 29;277(48):45793-802.
⇩ Epub 2002 Sep 13.
Bi-functional, substrate mimicking RNA inhibits
MSK1-mediated cAMP-response element-binding
protein phosphorylation and reveals magnesium
ion-dependent conformational changes of
Hamm J(1), Alessi DR, Biondi RM.
(1) Department of Biochemistry,
University of Dundee, Dundee, United Kingdom.
The design of specific inhibitors for protein
kinases is an important step toward elucidation
of intracellular signal transduction pathways
and to guide drug discovery programs. We
devised a model approach to generate specific,
competitive kinase inhibitors by isolating
substrate mimics containing two independent
binding sites with an anti-idiotype strategy
from combinatorial RNA libraries. As a general
test for the ability to generate highly
specific kinase inhibitors, we selected
the transcription factor cAMP-response
element-binding protein (CREB) that is
phosphorylated on the same serine residue
by the protein kinase MSK1 as well as by
RSK1. The sequences and structures of these
kinases are very similar, about 60% of their
amino acids are identical. Nevertheless,
we can demonstrate that the selected RNA
inhibitors inhibit specifically CREB phosphorylation
by MSK1 but do not affect CREB phosphorylation
by RSK1. The inhibitors interact preferentially
with the inactive form of MSK1. Furthermore,
we demonstrate that RNA ligands can be
conformation-specific probes, and this feature
allowed us to describe magnesium ion-dependent
conformational changes of MSK1 upon activation.
DOI: 10.1074/jbc.M205072200 PMID: 12235136
[Indexed for MEDLINE]