HER3ERBB3

HER3, also known as ErbB3, is a protein that plays a crucial role in cell growth and survival. It is a member of the epidermal growth factor receptor (EGFR) family of receptor tyrosine kinases. Unlike other members of this family, HER3 has a defective kinase domain, meaning it cannot effectively phosphorylate itself or other proteins. However, it is still a critical component of the HER signaling network.

HER3's primary function is to dimerize with other HER receptors, particularly HER2 (ErbB2). When HER3 binds to another HER receptor, it forms a potent signaling complex. This complex is then activated by ligands like heregulin, which bind to HER3. The heterodimerization with a constitutively active receptor like HER2 allows the complex to signal effectively, despite HER3's own kinase deficiency.

The HER3 signaling pathway is involved in a wide range of cellular processes, including cell proliferation, differentiation, migration, and survival. Dysregulation of HER3 signaling has been implicated in the development and progression of various cancers. For example, overexpression of HER3 or its signaling partners is frequently observed in breast, ovarian, and lung cancers. Consequently, HER3 has become a target for cancer therapies, with efforts focused on developing drugs that can inhibit its activity or disrupt its interactions with other HER receptors.