Binding of IGF I and IGF I-stimulated phosphorylation in canine renal basolateral membranes
To characterize the interaction of the renal proximal tubular cell with insulin like growth factor I (IGF I), we measured binding of /sup 125/I-IGF I to proximal tubular basolateral membranes from dog kidney and induced IGF I-stimulated phosphorylation of basolateral membranes. Specific binding of /sup 125/I-IGF I to basolateral membranes was observed that was half-maximal at between 10(-9) and 10(-8) M IGF I. /sup 125/I-IGF I was affinity cross-linked to a 135,000 Mr protein in basolateral membranes that was distinct from the alpha-subunit of the insulin receptor and from the IGF II receptor. IGF I-stimulated phosphorylation of a 92,000 Mr protein was effected in detergent-solubilized membranes incubated with 100 microM (gamma-/sup 32/P)ATP. The /sup 32/P-labeled protein was distinct from the beta-subunit of the insulin receptor, the /sup 32/P phosphorylation of which was stimulated by insulin. We conclude that specific receptors for IGF I are present in the basolateral membrane of the renal proximal tubular cell. Physiological actions of IGF I at this nephron site may occur through the binding of this peptide circulating in plasma, to specific basolateral membrane receptors, followed by IGF I stimulated phosphorylation.
- OSTI ID:
- 5092828
- Journal Information:
- Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States); ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL BONDS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DOGS
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
LIGHT NUCLEI
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORYLATION
PROTEINS
RADIOISOTOPES
RECEPTORS
TRACER TECHNIQUES
TUBULES
VERTEBRATES