Vertebrate mono-ADP-ribosyltransferases

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Mono-ADP-ribosylation is a reversible post-translational modification observed across diverse organisms.
• Arginine-specific ADP-ribosyltransferases (ADPRTs) are enzymes catalyzing this modification.
• Previous studies have identified and characterized various ADPRTs from different sources.

Purpose of the Study:

• To investigate the structural and functional diversity of arginine-specific ADPRTs.
• To characterize a specific mammalian ADPRT and determine its cellular localization and anchoring mechanism.

Main Methods:

• Purification and characterization of avian and mammalian ADPRTs.
• Cloning and sequence analysis of a rabbit skeletal muscle ADPRT.
• Transfection studies using mouse myotubes and NMU cells.
• Enzymatic release assays using phosphatidylinositol-specific phospholipase C.

Main Results:

• Avian ADPRTs (approx. 28 kDa) exhibit variations in physical, regulatory, and localization properties.
• A 38-kDa rabbit skeletal muscle ADPRT was purified and cloned, revealing features of GPI-anchored proteins.
• This mammalian ADPRT was found on the surface of myotubes and transfected cells, and released by PLC treatment.

Conclusions:

• Arginine-specific ADPRTs display significant diversity in their molecular structure.
• Cellular localization and anchoring mechanisms, such as GPI-anchoring, vary among ADPRTs.
• This diversity suggests varied physiological roles for arginine-specific ADP-ribosylation across different cell types and organisms.