Interaction between Her2 and Beclin-1 proteins underlies a new mechanism of reciprocal regulation.

Beclin-1 is a key regulator of autophagy that functions in the context of two phase-specific complexes in the initiation and maturation of autophagosomes. Its known interacting proteins include autophagy effectors, Bcl-2 family members, and organelle membrane anchor proteins. Here we report a newly identified interaction between Beclin-1 and the protein ...
tyrosine kinase receptor Her2. We demonstrate that in Her2-expressing breast carcinoma cells that do not succumb to lapatinib, this Her1/2 inhibitor disrupts the cell surface interaction between Her2 and Beclin-1. The data suggest that the ensuing autophagic response is correlatively associated with the release of Beclin-1 from its complex with Her2 and with the subsequent increase in cytosolic Beclin-1. Upon its interaction with Her2, Beclin-1 up-regulates the phosphorylation levels of Her2 and Akt. The Beclin-1 evolutionarily conserved domain is required both for the interaction of Beclin-1 with Her2 and for the increased Her2 and Akt phosphorylation. These findings shed new light on mechanisms involved in lapatinib-mediated autophagy in Her2-expressing breast carcinoma cell lines and in Beclin-1 signaling in these cells.
Mesh Terms:
Animals, Antineoplastic Agents, Apoptosis, Apoptosis Regulatory Proteins, Autophagy, Beclin-1, Cell Line, Tumor, Humans, Jurkat Cells, Lapatinib, MCF-7 Cells, Membrane Proteins, Mice, Microscopy, Electron, Transmission, Phagosomes, Phosphorylation, Protein Binding, Proto-Oncogene Proteins c-akt, Quinazolines, RNA Interference, Receptor, ErbB-2
J. Biol. Chem.
Date: Jul. 12, 2013
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