Characterization of Vasoactive Intestinal Peptide (VIP) receptors in mammalian lung
1986; Elsevier BV; Volume: 7; Issue: 5 Linguagem: Inglês
10.1016/0196-9781(86)90097-5
ISSN1873-5169
AutoresKenneth E.J. Dickinson, Michael Schächter, C. M. M. Miles, David H. Coy, Peter S. Sever,
Tópico(s)Chemical Synthesis and Analysis
Resumo125I-VIP bound specifically to sites on human, rat, guinea pig, and rabbit lung membranes with a dissociation constant (KD) of 60–200 pM and binding site maxima of 200–800 fmol/mg of protein. The presence of a second lower affinity site was detected but not investigated further. High affinity 125I-VIP binding was reversible and displaced by structurally related peptides with an order of potency: VIP > rGRF > PHI > hGRF > secretin=Ac Tyr1 D Phe2 GRF. 125I-VIP has been covalently incorporated into lung membranes using disuccinimidyl suberate. Sodium dodecyl sulfate-polyacrilamide gel electrophoresis of labeled human, rat, and rabbit lung membranes revealed major 125I-VIP-receptor complexes of: Mr=65,000, 56,000, and 64,000 daltons, respectively. Guinea pig lung membranes exhibited two 125I-VIP-receptor complexes of Mr=66,000 and 60,000 daltons. This labeling pattern probably reflects the presence of differentially glycosylated forms of the same receptor since treatment with neuroaminidase resulted in a single homogeneous band (Mr=57,000 daltons). Soluble covalently labeled VIP receptors from guinea pig and human lung bound to and were specifically eluted from agarose-linked wheat germ agglutinin columns. Our studies indicate that mammalian lung VIP receptors are glycoproteins containing terminal sialic acid residues.
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