Nuclear localization of bradykinin B₂ receptors reflects binding to the nuclear envelope protein lamin C

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• 作者：Masaoki Takano ; Akira Kanoh ; Katsumi Amako ; Mieko Otani ; Keiji Sano ; Michiko Kanazawa-Hamada ; Shogo Matsuyama
• 关键词：Heterodimer ; Bradykinin B2 receptor ; Lamin C ; Nuclear localization
• 刊名：European Journal of Pharmacology
• 出版年：15 January, 2014
• 年：2014
• 卷：723
• 期：Complete
• 页码：507-514
• 全文大小：1863 K

文摘

The mechanism of action of bradykinin (BK), a pro-inflammatory mediator, is thought to be mediated by specific cell surface membrane bradykinin B₂ receptors. Some evidence suggests that there are both intracellular and nuclear bradykinin B₂ receptors. This study identified proteins that interact with the C-terminus of the bradykinin B₂ receptor (in particular, the nuclear membrane protein lamin C), using the yeast two-hybrid system. The motif of the C-terminal domain (CT) mutant 303-320 in bradykinin B₂ receptor was identified as a lamin C protein binding motif. Immunohistochemistry revealed colocalization of FLAG- bradykinin B₂ receptor with HA-lamin C in the nucleus of HEK 293T cells. In situ proximity ligation assay (PLA) showed that FLAG-bradykinin B₂ receptor formed heterodimers with HA-lamin C in the nucleus. In addition, live cell fluorescence imaging showed that bradykinin B₂ receptor-EGFP was located in the nucleus and co-localized with HcRed-lamin C. Interestingly, neither BK addition nor bradykinin B₂ receptor CT mutation reduced the binding to lamin C or changed the distribution of bradykinin B₂ receptor. Taken together, these findings demonstrate that bradykinin B₂ receptor-lamin C heterodimers form in the nucleus independent of BK stimulation and CT mutation. We propose that heterodimerization of bradykinin B₂ receptor with lamin C is essential to nuclear localization of bradykinin B₂ receptor and plays an important role in cell signaling and function.