NEDD4 regulates ubiquitination and stability of the cell adhesion molecule IGPR-1 via lysosomal pathway

Journal of Biomedical Science

Linzi Sun¹  Razie Amraei¹  Nader Rahimi¹ 

[1] Department of Pathology, School of Medicine, Boston University Medical Campus, 670 Albany Street, 02118, Boston, MA, USA;

关键词: NEDD4;    IGPR-1;    TMIGD2;    CD28H;    UbcH6;    Ubiquitination;    K48-linked ubiquitination;    K63-linked ubiquitination;    Lysosomal degradation;    Melanoma;   

DOI  :  10.1186/s12929-021-00731-9

来源: Springer

【 摘 要 】

BackgroundThe cell adhesion molecule IGPR-1 regulates various critical cellular processes including, cell–cell adhesion, mechanosensing and autophagy and plays important roles in angiogenesis and tumor growth; however, the molecular mechanism governing the cell surface levels of IGPR-1 remains unknown.ResultsIn the present study, we used an in vitro ubiquitination assay and identified ubiquitin E3 ligase NEDD4 and the ubiquitin conjugating enzyme UbcH6 involved in the ubiquitination of IGPR-1. In vitro GST-pulldown and in vivo co-immunoprecipitation assays demonstrated that NEDD4 binds to IGPR-1. Over-expression of wild-type NEDD4 downregulated IGPR-1 and deletion of WW domains (1–4) of NEDD4 revoked its effects on IGPR-1. Knockdown of NEDD4 increased IGPR-1 levels in A375 melanoma cells. Deletion of 57 amino acids encompassing the polyproline rich (PPR) motifs on the C-terminus of IGPR-1 nullified its binding with NEDD4. Furthermore, we demonstrate that NEDD4 promotes K48- and K63-dependent polyubiquitination of IGPR-1. The NEDD4-mediated polyubiquitination of IGPR-1 stimulates lysosomal-dependent degradation of IGPR-1 as the treatment of cells with the lysosomal inhibitors, bafilomycine or ammonium chloride increased IGPR-1 levels ectopically expressed in HEK-293 cells and in multiple endogenously IGPR-1 expressing human skin melanoma cell lines.ConclusionsNEDD4 ubiquitin E3 ligase binds to and mediates polyubiquitination of IGPR-1 leading to its lysosomal-dependent degradation. NEDD4 is a key regulator of IGPR-1 expression with implication in the therapeutic targeting of IGPR-1 in human cancers.

【 授权许可】

CC BY