Cargando…

An ERAD‐independent role for rhomboid pseudoprotease Dfm1 in mediating sphingolipid homeostasis

Nearly one‐third of nascent proteins are initially targeted to the endoplasmic reticulum (ER), where they are correctly folded and assembled before being delivered to their final cellular destinations. To prevent the accumulation of misfolded membrane proteins, ER‐associated degradation (ERAD) remov...

Descripción completa

Detalles Bibliográficos
Autores principales: Bhaduri, Satarupa, Aguayo, Analine, Ohno, Yusuke, Proietto, Marco, Jung, Jasmine, Wang, Isabel, Kandel, Rachel, Singh, Narinderbir, Ibrahim, Ikran, Fulzele, Amit, Bennett, Eric J, Kihara, Akio, Neal, Sonya E
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9929635/
https://www.ncbi.nlm.nih.gov/pubmed/36350249
http://dx.doi.org/10.15252/embj.2022112275
Descripción
Sumario:Nearly one‐third of nascent proteins are initially targeted to the endoplasmic reticulum (ER), where they are correctly folded and assembled before being delivered to their final cellular destinations. To prevent the accumulation of misfolded membrane proteins, ER‐associated degradation (ERAD) removes these client proteins from the ER membrane to the cytosol in a process known as retrotranslocation. Our previous work demonstrated that rhomboid pseudoprotease Dfm1 is involved in the retrotranslocation of ubiquitinated membrane integral ERAD substrates. Herein, we found that Dfm1 associates with the SPOTS complex, which is composed of serine palmitoyltransferase (SPT) enzymes and accessory components that are critical for catalyzing the first rate‐limiting step of the sphingolipid biosynthesis pathway. Furthermore, Dfm1 employs an ERAD‐independent role for facilitating the ER export and endosome‐ and Golgi‐associated degradation (EGAD) of Orm2, which is a major antagonist of SPT activity. Given that the accumulation of human Orm2 homologs, ORMDLs, is associated with various pathologies, our study serves as a molecular foothold for understanding how dysregulation of sphingolipid metabolism leads to various diseases.