Cell biology of signalling: how members of the rhomboid-like superfamily regulate multiple pathways

细胞间的通讯是多细胞生物体中的一个重要过程，细胞间通讯的失调可能会产生严重的后果。iRhoms（失活菱形）是失活的假蛋白酶和菱形样超家族的成员。它们位于内质网（ER）中并参与细胞间信号传导。由于iRhom介导黑腹果蝇中ERAD系统（ER相关降解）对EGFR（表皮生长因子受体）配体的降解，因此其充当EGFR途径的负调节剂。另一方面，在哺乳动物中有两种iRhom（iRhom 1和iRhom 2），其通过介导跨膜蛋白酶ADAM 17（一种去整合素和金属蛋白酶）的运输和成熟而充当正调节剂。ADAM 17具有巨大的底物多样性，因此参与许多生理和病理生理过程，例如再生和发育，以及慢性炎症和肿瘤发展。其原因是，在其他底物中，EGFR和细胞因子的配体由ADAM 17蛋白水解释放。这证明了ADAM 17调节的重要性，因此也证明了iRhoms对于细胞间信号传导的重要性。iRhom介导的ADAM17运输的潜在机制既不清楚，也不知道是否存在ADAM17运输以外的其他iRhom功能。因此，拟议项目的目的是克隆人iRhom1和人iRhom2。该项目分为三个部分：1.表征ADAM 17和iRhoms 2之间的相互作用。保守的管腔iRhom结构域3的结构和功能表征。胞质区域的功能表征和该区域相互作用伴侣的鉴定

Summary Communication between cells is an important process in multicellular organisms and a dysregulation of the intercellular communication can have a severe outcome. iRhoms (inactive rhomboids) are inactive pseudoproteases and members of the rhomboid-like superfamily. They are located in the Endoplasmic reticulum (ER) and involved in intercellular signalling. Since iRhom mediates the degradation of ligands of the EGFR (epidermal growth factor receptor) by the ERAD-system (ER-associated degradation) in Drosophila melanogaster, it acts as a negative regulator of the EGFR pathway. On the other hand in mammalians there are two iRhoms (iRhom1 and iRhom2), which act as positive regulators by mediating the trafficking and maturation of the transmembrane protease ADAM17 (A Disintegrin And Metalloproteinase). ADAM17 has a huge substrate variety and therefore is involved in many physiological and pathophysiological processes such as regeneration and development but also chronic inflammation and tumour development. The reason for this is that among other substrates ligands of the EGFR and cytokines are proteolytically released by ADAM17. This demonstrates the importance of an ADAM17 regulation and therefore the significance of iRhoms for intercellular signalling. Neither the underlying mechanism of the iRhom-mediated trafficking of ADAM17 is clear nor is it known, if there are other iRhom functions beyond ADAM17 trafficking. Therefore the aim of the proposed project will be to characterise human iRhom1 and human iRhom2. The project is divided in three parts: 1. Characterising the interaction between ADAM17 and iRhoms 2. Structural and functional characterisation of the conserved luminal iRhom domain 3. Functional characterisation of the cytoplasmic region and identification of interaction partners of this region