A comparison of binding properties and structure of NGF receptor on PC12 pheochromocytoma and A875 melanoma cells

Journal Article · Sat Jan 01 04:00:00 EST 1983 · J. Cell. Biochem.; (United States)

DOI:https://doi.org/10.1002/jcb.240220404· OSTI ID:6905853

Buxser, S E; Watson, L; Johnson, G L

Rat PC12 pheochromocytoma and human A875 melanoma cells express nerve growth factor (NGF) receptors on their surfaces. Covalent crosslinking of bound /sup 125/I-NGF to PC12 or A875 intact cells or plasma membrane-enriched fractions resulted in labelling of a peptide doublet at Mr . 110,000 and a single labelled peptide at Mr . 200,000 for each of the cell and membrane preparations. PC12 cells exhibited biphasic binding properties with two apparent binding sites: KD . 5.2 nM sites and KD . 0.3 nM sites. The high-affinity PC12 binding sites were trypsin resistant, and /sup 125/I-NGF dissociated slowly from them. A875 cells exhibited sites with homogeneous properties (KD . 1.0 nM), all binding sites were trypsin sensitive, and /sup 125/I-NGF dissociated rapidly in the presence of unlabelled NGF. Membrane-enriched fractions from either cell type contained binding sites with a uniform low affinity (KD . 3 nM) that were trypsin sensitive, and /sup 125/I-NGF rapidly dissociated from them. Sixty to 80 percent of binding sites in membranes could be converted to the high-affinity, trypsin-resistant state by addition of wheat germ agglutinin (WGA). The loss of high-affinity, trypsin-resistant sites from PC12 cells during preparation of plasma membrane fractions does not appear to be the result of selective isolation of low-affinity sites or proteolytic degradation since there is a loss of /sup 125/I-NGF binding immediately after cell lysis which is not blocked by protease inhibitors. The differences between receptor properties on PC12 cells and on A875 cells apparently are the result of differences in the respective intracellular environments. Thus, cell components other than the binding unit of the NGF receptor may be responsible for the different properties of receptor.

• Research Organization: Department of Biochemistry, University of Massachusetts Medical Center, Worcester
• OSTI ID: 6905853
• Journal Information: J. Cell. Biochem.; (United States), Journal Name: J. Cell. Biochem.; (United States) Vol. 22:4; ISSN JCEBD
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL REACTIONS
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MEMBRANES
NERVE CELLS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
RECEPTORS
SOMATIC CELLS
STH
TRACER TECHNIQUES
TUMOR CELLS