A type i receptor serine/threonine kinase preferentially expressed
in pulmonary blood vessels.
Panchenko, Mikhail P., Mary C. Williams, Jerome S. Brody, and Qiang
Yu.
The Pulmonary Center and Department of Medicine, Anatomy, and
Biochemistry, Boston University School of Medicine, Boston, MA
APStracts 2:0193L, 1995.
Type II and type I receptor serine/threonine kinases (RSTKs) are
important components of the transmembrane signaling machinery that
allow cells to respond to the transforming growth factor [beta] super
family of cytokines (TGF-[beta]s). We have cloned from rat lung and
report here a 3935 bp cDNA encoding a type I RSTK previously
identified as R-3 (rat) or ALK-1 (human). Northern blot analysis
reveals that the R-3 mRNA is more abundant in lung than in other
adult rat tissues. By in situ hybridization, the R-3 transcripts are
found exclusively in the pulmonary vessels of all sizes, as well as
in aorta, vena cava and certain blood vessels of kidney, spleen,
heart and intestine. In most blood vessels a higher level of gene
expression is found in endothelium than in adjacent smooth muscle.
The R-3 transcripts are also found in splenic macrophages, as well as
within cells of marginal zone of the splenic lymphoid tissue. In
fetal rat lung the expression of R-3 transcripts differs from the
expression patterns of two other type I RSTKs. The R-3 is expressed
in vessels; the activin type IB receptor (R-2) is preferentially
expressed in putative developing airways, whereas the TGF-[beta] type
I receptor (R-4) transcripts appear to be ubiquitous. Our data
suggest that in vivo R-3 may propagate signaling of TGF-[beta]s in
selected cell types. The differential expression of multiple type I
receptors within different cell lineages may therefore define cell
specific responses to TGF-[beta]s.
Received 5 July 1995; accepted in final form 12 October 1995.
APS Manuscript Number L208-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95