Assays for transglutaminases in cell death

Area of Science:

• Biochemistry
• Cell Biology
• Dermatology

Background:

• Tissue transglutaminase (tTG), also known as transglutaminase type 2 (TGase 2), plays a role in programmed cell death (apoptosis).
• Epidermal keratinocytes utilize other TGases (TGase 1, 3, X) for terminal differentiation, a process leading to cell death that forms the skin barrier.
• Mutations in TGase 1 are associated with the skin disease lamellar ichthyosis.

Purpose of the Study:

• To explore the relationship between tissue transglutaminase (tTG) expression/activity and programmed cell death.
• To detail methodologies for assessing TGase function in cell death and disease.
• To provide guidelines for interpreting TGase involvement in cell death mechanisms.

Main Methods:

• In vivo and in vitro experimental models.
• mRNA and protein expression studies, transfection techniques.
• Analysis of N epsilon-(gamma-glutamyl)-lysine cross-links in apoptotic bodies.
• Production, purification, and characterization of recombinant TGases.
• Mutation identification and isolation of cross-linked bodies.

Main Results:

• Demonstrated a direct correlation between tTG expression/activity and apoptosis across various model systems.
• Confirmed tTG involvement in epidermal apoptosis under specific conditions.
• Highlighted the distinct roles of other TGases in keratinocyte terminal differentiation and skin barrier function.

Conclusions:

• TGases are fundamentally involved in cell death mechanisms, both apoptosis and terminal differentiation.
• Understanding TGase function is critical for studying cell death and related diseases like lamellar ichthyosis.
• Standardized assays and interpretation frameworks are necessary for comparative analysis of TGase activity in cell death.