Immunological demonstration of the accumulation of insulin, but not insulin receptors, in nuclei of insulin-treated cells

Journal Article · Fri Sep 01 04:00:00 EDT 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.17.6640· OSTI ID:6968919

Soler, A P; Thompson, K A; Smith, R M; Jarett, L ^[1]

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1. Univ. of Pennsylvania School of Medicine, Philadelphia (USA)

Although insulin is known to regulate nuclear-related processes, such as cell growth and gene transcription, the mechanisms involved are poorly understood. Previous studies suggested that translocation of insulin or its receptor to cell nuclei might be involved in some of these processes. The present investigation demonstrated that intact insulin, but not the insulin receptor, accumulated in nuclei of insulin-treated cells. Cell fractionation studies demonstrated that the nuclear accumulation of {sup 125}I-labeled insulin was time-, temperature-, and insulin-concentration-dependent. Electron microscopic immunocytochemistry demonstrated that the insulin that accumulated in the nucleus was immunologically intact and associated with the heterochromatin. Only 1% of the {sup 125}I-labeled insulin extracted from isolated nuclei was eluted from a Sephadex G-50 column as {sup 125}I-labeled tyrosine. Plasma membrane insulin receptors were not detected in the nucleus by immuno electron microscopy or when wheat germ agglutinin-purified extracts of the nuclei were subjected to PAGE, electrotransfer, and immunoblotting with anti-insulin receptor antibodies. These results suggested that internalized insulin dissociated from its receptor and accumulated in the nucleus without its membrane receptor. The authors propose that some of insulin's effects on nuclear function may be caused by the translocation of the intact and biologically active hormone to the nucleus and its binding to nuclear components in the heterochromatin.

• OSTI ID: 6968919
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 86:17; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMISTRY
CHROMATIN
CONNECTIVE TISSUE CELLS
CYTOCHEMISTRY
DAYS LIVING RADIOISOTOPES
DISEASES
DOSE-RESPONSE RELATIONSHIPS
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON MICROSCOPY
FIBROBLASTS
GENE REGULATION
HEPATOMAS
HORMONES
HYDROXY ACIDS
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MICROSCOPY
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SOMATIC CELLS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSCRIPTION
TUMOR CELLS
TYROSINE
UPTAKE
VERTEBRATES