11-cis-Acyl-CoA:retinol O-acyltransferase activity in the primary culture of chicken Muller cells.
11-cis-Acyl-CoA:retinol O-acyltransferase activity in the primary culture of chicken Muller cells.
复制标题
11-顺式酰基辅酶A：鸡 Muller 细胞原代培养物中的视黄醇 O-酰基转移酶活性。
DOI：
10.1021/bi060928p
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发表时间：
2006
期刊：
影响因子：
2.9
通讯作者：
Tsin,AndrewTC
中科院分区：
文献类型：
--
作者：
Muniz,Alberto;Villazana-Espinoza,EliaT;Thackeray,Bridget;Tsin,AndrewTC
A novel retinoid cycle has recently been identified in the cone-dominated chicken retina, and this cone cycle accumulates 11-cis-retinyl esters upon light adaptation. The purpose of this study is to investigate how 11-cis-retinyl esters are formed in the retina. Primary cultures of chicken Muller cells and cell membrane were incubated with all-trans-or 11-cis-retinol to study retinyl ester synthesis. In Muller cells, esterification of 11-cis-retinol was four times greater than esterification of all-trans-retinol. In the presence of palmitoyl-CoA and CRALBP, Muller cell membranes synthesized 11-cis-retinyl ester from 11-cis-retinol at a rate which was 20-fold higher than that of all-trans-retinyl ester. In the absence of CRALBP, 11-cis-retinyl ester synthesis was greatly reduced (by 7-fold). In the absence of palmitoyl-CoA, retinyl ester synthesis was not observed. Muller cell membranes incubated with radiolabeled palmitoyl-CoA resulted in the transfer of the labeled acyl group to retinol. This acyl transfer was greatly reduced in the presence of progesterone, a known ARAT inhibitor. 11-cis-ARAT activity remained unchanged when assayed in the presence of all-trans-retinol, suggesting a distinct catalytic activity from that of all-trans-ARAT. Apparent kinetic rates for 11-cis-ARAT were 0.135 nmol min-1mg-1(Vmax) and 11.25 μM (KM) and for all-trans-ARAT were 0.0065 nmol min-1mg-1(Vmax) and 28.88 μM (KM). Our data indicate that Muller cells in the chicken retina possess 11-cis-ARAT activity, thus providing an explanation for the accumulation of 11-cis-retinyl esters in the cone cycle.
