Inhibition of AT1 Receptor Internalization by Concanavalin A Blocks Angiotensin II-induced ERK Activation in Vascular Smooth Muscle Cells
| Autor: | Trinita G. Fitzgerald, Tadashi Inagami, Toshihide Nishishita, Erwin J. Landon, Hua Tang |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
MAPK/ERK pathway
medicine.medical_specialty Angiotensin II receptor type 1 Chemistry media_common.quotation_subject chemical and pharmacologic phenomena Cell Biology Biochemistry Cell biology Endocrinology Growth factor receptor Epidermal growth factor Internal medicine Interleukin-21 receptor cardiovascular system medicine Enzyme-linked receptor Internalization Molecular Biology Tyrosine kinase hormones hormone substitutes and hormone antagonists media_common |
| Zdroj: | Journal of Biological Chemistry. 275:13420-13426 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.275.18.13420 |
| Popis: | Recent studies of beta(2)-adrenergic receptor suggest that agonist-promoted receptor internalization may play an important role in extracellular signal-regulated kinase (ERK) activation by G protein-coupled receptors. In the present study, we explored the effects of angiotensin II (Ang II) type-1 receptor (AT(1)) internalization on Ang II-induced activation of ERK using the receptor internalization blocker concanavalin A (ConA) and the carboxyl terminus-truncated receptor mutants with impaired internalization. ConA inhibited AT(1) receptor internalization without affecting ligand binding to the receptor, Ang II-induced generation of second messengers, and activation of tyrosine kinases Src and Pyk2 in vascular smooth muscle cells (VSMC). ConA blocked ERK activation evoked by Ang II and the calcium ionophore A23187. Impairment of AT(1) receptor internalization by truncating the receptor carboxyl terminus did not affect Ang II-induced ERK activation. ConA induced proteolytic cleavage of the epidermal growth factor (EGF) receptor at carboxyl terminus and abolished Ang II-induced transactivation of the EGF receptor, which is critical for ERK activation by Ang II in VSMC. ConA also induced proteolysis of erbB-2 but not platelet-derived growth factor receptor. Thus, ConA blocks Ang II-induced ERK activation in VSMC through a distinct mechanism, the ConA-mediated proteolysis of the EGF receptor. |
| Databáze: | OpenAIRE |
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