Glutathione S-transferase P 1 (GSTP1) (GSTP1)

Glutathione S-transferase P 1 (GSTP1) is a multifunctional enzyme that serves as the primary zeaxanthin-binding protein in the human macula (Bhosale et al., 2004). Located within the retinal cell membranes and cytoplasm of the Henle fiber layer, GSTP1 specifically binds and stabilizes zeaxanthin, a xanthophyll carotenoid essential for ocular health (Li et al., 2011). This interaction is crucial for maintaining macular pigment optical density, which protects the retina by filtering high-energy blue light and providing potent antioxidant defense against photo-oxidative damage (Bernstein et al., 2016). Dysregulation or low levels of GSTP1-bound zeaxanthin are strongly associated with the development and progression of age-related macular degeneration (AMD) (UniProt P09211). Beyond its role in the eye, GSTP1 is a key detoxification enzyme involved in conjugating glutathione to electrophilic compounds, and its expression levels are often altered in various cancers, influencing drug resistance and susceptibility to environmental toxins (PubMed: 15159469). It also acts as a regulator of the JNK signaling pathway, thereby influencing apoptosis and cellular stress responses (UniProt P09211).

Other names

Zeaxanthin-binding proteinZBPGSTP1-1Glutathione S-transferase pi 1GST3Glutathione S-transferase P

Drugs and nutrients interact with GSTP1 either as ligands that are sequestered and stabilized (e.g., zeaxanthin for retinal protection) or as inhibitors and prodrug substrates that modulate its enzymatic and signaling activities (e.g., ezatiostat for hematological conditions or canfosfamide for cancer treatment).