HER-2 and ERBB2 gene products exhibit what type of activity?

The HER-2 and ERBB2 gene products are known to exhibit tyrosine kinase activity, which is a vital aspect of their function in cellular signaling pathways. These proteins are part of the epidermal growth factor receptor (EGFR) family and play a significant role in various cellular processes, including cell division, differentiation, and survival.

Tyrosine kinases transfer phosphate groups from ATP to specific tyrosine residues on target proteins, leading to a conformational change that typically activates or deactivates those proteins. In the case of HER-2, when it is activated, it can initiate a cascade of downstream signaling pathways that can promote cell proliferation and survival, contributing to tumorigenesis in certain cancers, such as breast cancer.

The presence of tyrosine kinase activity in these gene products is crucial because it helps to understand their role in oncogenic signaling and the development of targeted therapies, such as trastuzumab (Herceptin), which specifically targets the HER-2 protein in cancer treatment. This knowledge is essential in molecular biology and oncology for the development of therapeutic strategies against HER-2 positive malignancies.