Lane S R, Liu Y
Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City 73190, U.S.A.
J Neurochem. 1997 Nov;69(5):1864-9. doi: 10.1046/j.1471-4159.1997.69051864.x.
SNAP-25 (synaptosomal associated protein of 25 kDa) is a neural specific protein that has been implicated in the synaptic vesicle docking and fusion process. It is tightly associated with membranes, and it is one of the major palmitoylated proteins found in neurons. The functional role of palmitoylation for SNAP-25 is unclear. In this report, we show that the palmitate of SNAP-25 is rapidly turned over in PC12 cells, with a half-life of approximately 3 h, and the half-life for the protein is 8 h. Mutation of Cys to Ser at positions 85, 88, 90, and 92 reduced the palmitoylation to 9, 21, 42, and 35% of the wild-type protein, respectively. Additional mutations of either Cys(85,88) or Cys(90,92) nearly abolished palmitoylation of the protein. A similar effect on membrane binding for the mutant SNAP-25 was observed, which correlated with the degree of palmitoylation. These results suggest that all four Cys residues are involved in palmitoylation and that membrane association of SNAP-25 may be regulated through dynamic palmitoylation.
SNAP-25（25 kDa突触体相关蛋白）是一种神经特异性蛋白，与突触小泡对接和融合过程有关。它与膜紧密结合，是神经元中发现的主要棕榈酰化蛋白之一。SNAP-25棕榈酰化的功能作用尚不清楚。在本报告中，我们表明，SNAP-25的棕榈酸酯在PC12细胞中快速周转，半衰期约为3小时，而该蛋白的半衰期为8小时。将第85、88、90和92位的半胱氨酸突变为丝氨酸，分别将棕榈酰化降低至野生型蛋白的9%、21%、42%和35%。Cys(85,88)或Cys(90,92)的额外突变几乎消除了该蛋白的棕榈酰化。观察到突变型SNAP-25对膜结合有类似影响，这与棕榈酰化程度相关。这些结果表明，所有四个半胱氨酸残基都参与棕榈酰化，并且SNAP-25的膜结合可能通过动态棕榈酰化来调节。
