Proteasome is a protein degradation complex that plays a major role in maintaining cellular homeostasis. Despite extensive efforts to identify protein substrates that are degraded through ubiquitination, the regulation of proteasome activity itself under diverse signals is poorly understood. In this study, we have isolated iRhom1 as a stimulator of proteasome activity from genome-wide functional screening using cDNA expression and an unstable GFP-degron. Downregulation of iRhom1 reduced enzymatic activity of proteasome complexes and overexpression of iRhom1 enhanced it. Native-gel and fractionation analyses revealed that knockdown of iRhom1 expression impaired the assembly of the proteasome complexes. The expression of iRhom1 was increased by endoplasmic reticulum (ER) stressors, such as thapsigargin and tunicamycin, leading to the enhancement of proteasome activity, especially in ER-containing microsomes. iRhom1 interacted with the 20S proteasome assembly chaperones PAC1 and PAC2, affecting their protein stability. Moreover, knockdown of iRhom1 expression impaired the dimerization of PAC1 and PAC2 under ER stress. In addition, iRhom1 deficiency in D. melanogaster accelerated the rough-eye phenotype of mutant Huntingtin, while transgenic flies expressing either human iRhom1 or Drosophila iRhom showed rescue of the rough-eye phenotype. Together, these results identify a novel regulator of proteasome activity, iRhom1, which functions via PAC1/2 under ER stress.

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The manager of condominium is a representative of the unit owners’ association of condominium. The unit owners live together in condominium building, form the unit owners’ association and manage the building together. A manager shall exercise leadership for all members with responsibility as a representative of the unit owners’ association and should listen to the unit onwers’ opinions while communicating with them. However, if a corporation becomes a representative, it is unclear who should be responsible for the decision of the corporation, because not only representative but also general meetings, audits, and bylaws affect the judgments made by corporation. It is difficult to expect the corporation itself to lead unit owners’ association with leadership. For this reason, it is generally accepted that a corporation cannot become a director or a representative of a legal entity in Korea. Therefore the manager of condominium needs not be a unit owner, but must be a natural person. Whether a corporation can be a manager is closely related to the question of whether a management company can be a manager. In order for a management company to become a manager, a corporation should be allowed to be a manager. However, regardless of whether a corporation can be a manager, a management company should not a manager. The management company is a contract party of a management contract with the unit owners’ association, and if the contract party that enters into the contract with unit owners’ association becomes the representative of it, the interests of unit owners’ association and the management company conflict. A corporation can be a management committee member of condominium? Since the Condominium Act stipulates that only the unit owner can be a management committee member and does not allow the representative of the corporation which is a unit owner to be a management committee member. a corporation which is a unit owner can become a management committee member. However,