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-Structure paper
タイトル | Activation of the insulin receptor by insulin-like growth factor 2. |
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ジャーナル・号・ページ | Nat Commun, Vol. 15, Issue 1, Page 2609, Year 2024 |
掲載日 | 2024年3月23日 |
著者 | Weidong An / Catherine Hall / Jie Li / Albert Hung / Jiayi Wu / Junhee Park / Liwei Wang / Xiao-Chen Bai / Eunhee Choi / |
PubMed 要旨 | Insulin receptor (IR) controls growth and metabolism. Insulin-like growth factor 2 (IGF2) has different binding properties on two IR isoforms, mimicking insulin's function. However, the molecular ...Insulin receptor (IR) controls growth and metabolism. Insulin-like growth factor 2 (IGF2) has different binding properties on two IR isoforms, mimicking insulin's function. However, the molecular mechanism underlying IGF2-induced IR activation remains unclear. Here, we present cryo-EM structures of full-length human long isoform IR (IR-B) in both the inactive and IGF2-bound active states, and short isoform IR (IR-A) in the IGF2-bound active state. Under saturated IGF2 concentrations, both the IR-A and IR-B adopt predominantly asymmetric conformations with two or three IGF2s bound at site-1 and site-2, which differs from that insulin saturated IR forms an exclusively T-shaped symmetric conformation. IGF2 exhibits a relatively weak binding to IR site-2 compared to insulin, making it less potent in promoting full IR activation. Cell-based experiments validated the functional importance of IGF2 binding to two distinct binding sites in optimal IR signaling and trafficking. In the inactive state, the C-terminus of α-CT of IR-B contacts FnIII-2 domain of the same protomer, hindering its threading into the C-loop of IGF2, thus reducing the association rate of IGF2 with IR-B. Collectively, our studies demonstrate the activation mechanism of IR by IGF2 and reveal the molecular basis underlying the different affinity of IGF2 to IR-A and IR-B. |
リンク | Nat Commun / PubMed:38521788 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.6 - 4.2 Å |
構造データ | EMDB-41877, PDB-8u4b: EMDB-41878, PDB-8u4c: EMDB-41880, PDB-8u4e: EMDB-43279, PDB-8vjb: EMDB-43280, PDB-8vjc: |
由来 |
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キーワード | SIGNALING PROTEIN / Insulin receptor / IGF2 / RTK |