Two Faces of Glutaminase GLS2 in Carcinogenesis

In rapidly proliferating cancer cells, glutamine is a major source of energy and building blocks. Increased glutamine uptake and enhanced glutaminolysis are key metabolic features of many cancers. Glutamine is metabolized by glutaminase (GA), which is encoded by two genes: GLS and GLS2. In contrast to isoforms arising from the GLS gene, which clearly act as oncoproteins, the role of GLS2 products in tumorigenesis is far from well understood. While in some cancer types GLS2 is overexpressed and drives cancer development, in some other types it is downregulated and behaves as a tumor suppressor gene. In this review, we describe the essential functions and regulatory mechanisms of human GLS2 and the cellular compartments in which GLS2 has been localized. Furthermore, we present the context-dependent oncogenic and tumor-suppressor properties of GLS2, and delve into the mechanisms underlying these phenomena.