SARM1 is a multi-functional NAD(P)ase with prominent base exchange activity, all regulated bymultiple physiologically relevant NAD metabolites.


Type
Article
Change log
Authors
Angeletti, Carlo 
Amici, Adolfo 
Gilley, Jonathan 
Trapanotto, Antonio G 
Abstract

SARM1 is an NAD(P) glycohydrolase and TLR adapter with an essential, prodegenerative role in programmed axon death (Wallerian degeneration). Like other NAD(P)ases, it catalyzes multiple reactions that need to be fully investigated. Here, we compare these multiple activities for recombinant human SARM1, human CD38, and Aplysia californica ADP ribosyl cyclase. SARM1 has the highest transglycosidation (base exchange) activity at neutral pH and with some bases this dominates NAD(P) hydrolysis and cyclization. All SARM1 activities, including base exchange at neutral pH, are activated by an increased NMN:NAD ratio, at physiological levels of both metabolites. SARM1 base exchange occurs also in DRG neurons and is thus a very likely physiological source of calcium-mobilizing agent NaADP. Finally, we identify regulation by free pyridines, NADP, and nicotinic acid riboside (NaR) on SARM1, all of therapeutic interest. Understanding which specific SARM1 function(s) is responsible for axon degeneration is essential for its targeting in disease.

Description
Keywords
Biological sciences, Molecular physiology, Neuroscience
Journal Title
iScience
Conference Name
Journal ISSN
2589-0042
2589-0042
Volume Title
25
Publisher
Elsevier BV
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/S009582/1)
Wellcome Trust (210904/Z/18/Z)