Title: The endoplasmic reticulum acetyltransferases ATase1/NAT8B and ATase2/NAT8 are differentially regulated to adjust engagement of the secretory pathway
Legend: ATase1 and ATase2 share enzyme kinetic properties and acetyl-CoA binding site but differ in the allosteric posket. (A-B) Lineweaver-Burk plots of the acetyl-CoA:lysine acetyltransferase activity of purified, recombinant ATase1 or ATase2 expressed in E. coli. Each reaction included 200 ng purified enzyme. (C-E) Predicted structure of the acetyl-CoA binding pocket for ATase1 (C, green) and ATase2 (D, orange). The black boxes outline the zoomed-in region shown in panel E. Side-chain residues predicted to stabilize the acetyl-CoA binding are shown as colored sticks. (F-G) Predicted structure of the K99 residue and surrounding microenvironment in ATase1 and ATase2. Isosurface charge is displayed from positive (red) to negative (blue). The proposed peptidyl-lysine pocket (green spheres), regulatory loop (black line), and gating loops (yellow, magenta lines) are illustrated for orientation.
Citation: Rigby MJ, Ding Y, Farrugia MA, Feig M, Cortese GP, Mitchell H, Burger C, Puglielli L. (2020). The endoplasmic reticulum acetyltransferases ATase1/NAT8B and ATase2/NAT8 are differentially regulated to adjust engagement of the secretory pathway. Journal of Neurochemestry. 2020 Jan 16:e14958. doi: 10.1111/jnc.14958.
Abstract: Nε-lysine acetylation of nascent glycoproteins within the endoplasmic reticulum (ER) lumen regulates the efficiency of the secretory pathway. The ER acetylation machinery consists of the membrane transporter, acetyl-CoA transporter 1 (AT-1/SLC33A1), and two acetyltransferases, ATase1/NAT8B and ATase2/NAT8. Dysfunctional ER acetylation is associated with severe neurological diseases with duplication of AT-1/SLC33A1 being associated with autism spectrum disorder, intellectual disability, and dysmorphism. Neuron-specific AT-1 overexpression in the mouse alters neuron morphology and function, causing an autism-like phenotype, indicating that ER acetylation plays a key role in neurophysiology. As such, characterizing the molecular mechanisms that regulate the acetylation machinery could reveal critical information about its biology. By using structure-biochemistry approaches, we discovered that ATase1 and ATase2 share enzymatic properties but differ in that ATase1 is post-translationally regulated via acetylation.
About the Lab: The Puglielli Lab’s research interests focus on molecular mechanisms of neurodevelopment and neurodegeneration. The laboratory employs a combination of biochemical, cellular, molecular, and genetic approaches in in vitro, ex vivo and in vivo models.