Comparison of solubilized and purified plasma membrane and nuclear insulin receptors
Prior studies have detected biochemical and immunological differences between insulin receptors in plasma membranes and isolated nuclei. To further investigate these receptors, they were solubilized in Triton X-100 partially purified by wheat germ agglutinin-agarose chromatography. In these preparations, the nuclear and plasma membrane receptors had very similar pH optima (pH 8.0) and reactivities to a group of polyclonal antireceptor antibodies. Further, both membrane preparations had identical binding activities when labeled insulin was competed for by unlabeled insulin (50% inhibition at 800 pM). Next, nuclear and plasma membranes were solubilized and purified to homogeneity by wheat germ agglutinin-agarose and insulin-agarose chromatography. In both receptors, labeled insulin was covalently cross-linked to a protein of 130 kilodaltons representing the insulin receptor ..cap alpha.. subunit. When preparations of both receptors were incubated with insulin and then adenosine 5'-(..gamma..-/sup 32/P)triphosphate, a protein of 95 kilodaltons representing the insulin receptor ..beta.. subunit was phosphorylated in a dose-dependent manner. These studies indicate, therefore, that solubilized plasma membrane and nuclear insulin receptors have similar structures and biochemical properties, and they suggest that they are the same (or very similar) proteins.
- Research Organization:
- Mount Zion Hospital and Medical Center, San Francisco, CA
- OSTI ID:
- 5438212
- Journal Information:
- Biochemistry; (United States), Vol. 27:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Solubilized placental membrane protein inhibits insulin receptor tyrosine kinase activity
Differences in the sites of phosphorylation of the insulin receptor in vivo and in vitro
Related Subjects
INSULIN
CROSS-LINKING
RECEPTORS
MOLECULAR STRUCTURE
PURIFICATION
ATP
CELL MEMBRANES
DOSE-RESPONSE RELATIONSHIPS
PH VALUE
PHOSPHORUS 32
PHOSPHORYLATION
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CELL CONSTITUENTS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
HORMONES
ISOTOPES
LIGHT NUCLEI
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS ISOTOPES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques