Preubiquitinated chimeric ErbB2 is constitutively endocytosed and subsequently degraded in lysosomes

Journal Article · Fri Feb 01 04:00:00 EST 2013 · Experimental Cell Research

DOI:https://doi.org/10.1016/J.YEXCR.2012.10.010· OSTI ID:22215478

Vuong, Tram Thu ^[1]; Berger, Christian ^[2]; Bertelsen, Vibeke; Rødland, Marianne Skeie ^[1]; Stang, Espen ^[2]

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1. Institute of Clinical Medicine, University of Oslo, Rikshospitalet, 0027 Oslo (Norway)
2. Department of Pathology, Oslo University Hospital, Rikshospitalet, P.O. Box 4950 Nydalen, 0424 Oslo (Norway)

The oncoprotein ErbB2 is endocytosis-deficient, probably due to its interaction with Heat shock protein 90. We previously demonstrated that clathrin-dependent endocytosis of ErbB2 is induced upon incubation of cells with Ansamycin derivatives, such as geldanamycin and its derivative 17-AAG. Furthermore, we have previously demonstrated that a preubiquitinated chimeric EGFR (EGFR-Ub{sub 4}) is constitutively endocytosed in a clathrin-dependent manner. We now demonstrate that also an ErbB2-Ub{sub 4} chimera is endocytosed constitutively and clathrin-dependently. Upon expression, the ErbB2-Ub{sub 4} was further ubiquitinated, and by Western blotting, we demonstrated the formation of both Lys48-linked and Lys63-linked polyubiquitin chains. ErbB2-Ub{sub 4} was constitutively internalized and eventually sorted to late endosomes and lysosomes where the fusion protein was degraded. ErbB2-Ub{sub 4} was not cleaved prior to internalization. Interestingly, over-expression of Ubiquitin Interaction Motif-containing dominant negative fragments of the clathrin adaptor proteins epsin1 and Eps15 negatively affected endocytosis of ErbB2. Altogether, this argues that ubiquitination is sufficient to induce clathrin-mediated endocytosis and lysosomal degradation of the otherwise plasma membrane localized ErbB2. Also, it appears that C-terminal cleavage is not required for endocytosis. -- Highlights: ► A chimera containing ErbB2 and a tetra-Ubiquitin chain internalizes constitutively. ► Receptor fragmentation is not required for endocytosis of ErbB2. ► Ubiquitination is sufficient to induce endocytosis and degradation of ErbB2. ► ErbB2-Ub4 is internalized clathrin-dependently.

• OSTI ID: 22215478
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 3 Vol. 319; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANTIGENS
CHIMERAS
GROWTH FACTORS
HEAT-SHOCK PROTEINS
LYSOSOMES
RECEPTORS
TYROSINE