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Insulin receptors in rat brain: insulin stimulates phosphorylation of its receptor β‐subunit
Author(s) -
Gammeltoft Steen,
Kowalski Aline,
Fehlmann Max,
van Obberghen Emmanuel
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80879-0
Subject(s) - insulin receptor , receptor , insulin , phosphorylation , protein subunit , endocrinology , insulin receptor substrate , medicine , chemistry , biology , biochemistry , insulin resistance , gene
In rat brain cortex synaptosomes insulin stimulated the phosphorylation of its own receptor β‐subunit (94 kDa) as identified by immunoprecipitation with anti‐insulin or anti‐receptor antiserum. The receptor α‐subunit (115 kDa) was characterized by specific labeling with 125 I‐labeled photoreactive insulin. These observations indicate that: (i) insulin receptors in brain are composed of α‐subunits which bind insulin, and β‐subunits, the phosphorylation of which can be stimulated by insulin; (ii) the size of α‐subunits in brain is significantly smaller than in other tissues (115 vs 130 kDa), whereas β‐subunits (94 kDa) are identical. We suggest that brain insulin receptors represent a subtype regarding their binding function, whereas their enzyme function is more conserved.