According to a research published by Cell Press in an issue of Molecular Cell, valuable insight has been achieved into a previously undescribed mechanism that is considered to facilitate regulation of a prominent carcinoma-linked protein.

The research is seen as a potential roadmap to improve the understanding of fundamental processes contributing to breast cancer. It was remarked that steroid receptor coactivator-3 (SRC-3/AIB1) that plays a critical role in cell growth is often over expressed.

From News-Medical.Net:

The researchers found that aPKC stabilized cellular SRC-3 protein levels by inducing phosphorylation of a particular region of SRC-3. Specifically, phosphorylation of C-terminal residues induced a conformational change that made SRC-3 more resistant to degradation by the core proteasome. This effect of aPKC required estrogen and estrogen receptor and was not supported by other steroid receptors, suggesting that aPKC-mediated SRC-3 stabilization is a receptor-selective event. These results reveal a mechanism that links aPKC with estrogen-dependent growth and tumorigenesis and provide yet another layer of control for regulating levels of the SRC-3 oncogenic protein.

“Our data describe a new regulatory mechanism for SRC-3 protein turnover which may play an important role in regulating SRC-3 levels in normal and oncogenic cell growth,” offers Dr. O’Malley. “We propose that when aPKC is overexpressed in cancer cells, the consequence is increased SRC-3 function and powerful enhancement of estrogen-receptor target gene transcription and promotion of estrogen-dependent cell growth in cancer cells such as breast.”

It was found that aPKC (atypical protein Kinase C) is responsible for alleviating cellular SRC-3 protein levels by inducing phosphorylation of a specific region of SRC-3, as per Dr. Bert O’Malley from the Baylor College of Medicine.