A cellular model of albumin endocytosis uncovers a link between membrane and nuclear proteins

Autor: Tomohiro Udagawa, Koji L. Ode, Yuko Kajiho, Masaomi Nangaku, Seiya Urae, Akira Oka, Masami Nagahama, Akihiko Saito, Shoichiro Kanda, Hiroki R. Ueda, Yutaka Harita
Rok vydání: 2019
Předmět:
Zdroj: Journal of cell science. 133(13)
ISSN: 1477-9137
Popis: Cubilin (CUBN) and amnionless (AMN), expressed in kidney and intestine, form a multiligand receptor complex called CUBAM that plays a crucial role in albumin absorption. To date, the mechanism of albumin endocytosis mediated by CUBAM remains to be elucidated. Here, we established an assay to quantitatively evaluate the albumin uptake by CUBAM using cells expressing full-length CUBN, which elucidated the crucial role of C-terminal part of CUBN and endocytosis signal motifs of AMN in albumin endocytosis. We also demonstrated that nuclear valosin-containing protein-like 2 (NVL2), an interacting protein of AMN, is involved in this process. While NVL2 was mainly localized in the nucleolus in cells without AMN expression, it was translocated to the extranuclear compartment when co-expressed with AMN. NVL2 knockdown significantly impaired the internalization of the CUBN-albumin complex in cultured cells, demonstrating an involvement of NVL2 in endocytic regulation. These findings uncover a link between membrane and nucleolar proteins which is involved in endocytic processes.
Databáze: OpenAIRE