Gga2, short for Golgi-localized, γ-adaptin ear-containing, ADP ribosylation factor-binding protein 2, is involved in protein trafficking and sorting pathways. It plays a crucial role in maintaining the steady-state expression of various receptors, which is essential for normal cell function and growth. It is associated with pathways related to receptor-mediated cell signaling and endosomal trafficking [1,2,3,4].

Gga2-depletion by RNAi greatly reduced steady-state expression of EGFR, reflecting enhanced lysosomal degradation of EGFR, and Gga2-depleted cells had reduced EGF signaling and cell proliferation in cell culture and xenograft experiments, indicating its role in promoting cell growth through interacting with EGFR [1]. Depletion of Gga2 also significantly suppressed EGFR recycling to the plasma membrane, reducing the cell surface expression of EGFR and suppressing the growth of H1975 cancer cells in culture and xenograft model [2]. Moreover, Gga2 silencing limits active β1-integrin levels in focal adhesions and decreases cancer cell migration and invasion, showing its role in integrin-mediated cell migration [3]. In Saccharomyces cerevisiae, Gga2 is required for Golgi-to-endosomal trafficking of Arn1, a ferrichrome transporter [5].

In conclusion, Gga2 is vital for maintaining receptor expression, cell growth, and cell migration. Its role in these processes has implications for cancer research, as its dysregulation can impact EGFR-mediated tumorigenesis and integrin-related cancer cell invasion. Understanding Gga2's function through loss-of-function experiments provides insights into potential therapeutic targets for cancer treatment.