Acyl-CoA wax alcohol acyltransferase 2: its regulation and actions in support of color vision

William S Blaner

doi:10.1194/jlr.c075838

Abstract

Acyl-CoA wax alcohol acyltransferase 2: its regulation and actions in support of color vision

Highlights

The enzyme acyl-CoA wax alcohol acyltransferase 2 (AWAT2), which is commonly referred to as multifunctional O-acyltransferase (MFAT), was first identified more than a decade ago by several groups as an enzyme responsible for wax monoester biosynthesis in the skin [1,2,3]
Golczak and colleagues [6] propose that the binding of 11-cis-retinoids to AWAT2 in Müller cells causes a ligandinduced structural change that makes the enzyme more efficient in catalyzing 11-cis-retinol esterification. This increased efficiency is specific for 11-cis-retinol esterification, at the expense of the 9-cis, 13-cis, and all-trans-retinol isomers that may be present in the cell, driving 11-cisretinyl ester accumulation and flux. This is important because visual pigment regeneration in cones relies on the accumulation of 11-cis-retinyl esters facilitated by AWAT2
Diacylglycerol acyl-CoA acyltransferase 1 (DGAT1) is widely expressed in many tissues; i.e., in the liver where relatively high levels of retinyl esters are found, there is no evidence that DGAT1 plays a role in catalyzing retinyl ester formation in these tissues

Summary

Introduction

The enzyme acyl-CoA wax alcohol acyltransferase 2 (AWAT2), which is commonly referred to as multifunctional O-acyltransferase (MFAT), was first identified more than a decade ago by several groups as an enzyme responsible for wax monoester biosynthesis in the skin [1,2,3]. The studies being reported by Golczak et al [6] considerably extend biochemical understanding of what has been referred to as the cone-specific retinoid (visual) cycle [see Fig. 1 and [7]]. In the cone-specific cycle, all-trans-retinol is thought to undergo enzyme-catalyzed isomerization to 11-cis-retinol in the Müller cells via the actions of dihydroceramide desaturase-1 (DES-1) [9].

Results

Conclusion