Kim Yoojin, Ramirez-Montealegre Denia, Pearce David A
Center for Aging and Developmental Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15458-62. doi: 10.1073/pnas.2136651100. Epub 2003 Dec 5.
In Saccharomyces cerevisiae, transport of arginine into the vacuole has previously been shown to be facilitated by a putative H+/arginine antiport. We confirm that transport of arginine into isolated yeast vacuoles requires ATP and we demonstrate a requirement for a functional vacuolar H+-ATPase. We previously reported that deletion of BTN1 (btn1-delta), an ortholog of the human Batten disease gene CLN3, resulted in a decrease in vacuolar pH during early growth. We report that this altered vacuolar pH in btn1-delta strains underlies a lack of arginine transport into the vacuole, which results in a depletion of endogenous vacuolar arginine levels. This arginine transport defect in btn1-delta is complemented by expression of either BTN1 or the human CLN3 gene and strongly suggests a function for transport of, or regulation of the transport of, basic amino acids into the vacuole or lysosome for yeast Btn1p, and human CLN3 protein, respectively. We propose that defective transport at the lysosomal membrane caused by an absence of functional CLN3 is the primary biochemical defect that results in Batten disease.
在酿酒酵母中，先前已表明精氨酸向液泡的转运是由一种假定的H⁺/精氨酸反向转运体促进的。我们证实精氨酸向分离的酵母液泡的转运需要ATP，并且我们证明了对功能性液泡H⁺-ATP酶的需求。我们先前报道，人类巴顿病基因CLN3的直系同源基因BTN1（btn1-Δ）的缺失导致早期生长期间液泡pH值降低。我们报道，btn1-Δ菌株中这种改变的液泡pH值是精氨酸向液泡转运缺乏的基础，这导致内源性液泡精氨酸水平的耗尽。btn1-Δ中的这种精氨酸转运缺陷可通过BTN1或人类CLN3基因的表达得到互补，这强烈表明酵母Btn1p和人类CLN3蛋白分别在将碱性氨基酸转运到液泡或溶酶体中或调节这种转运方面具有功能。我们提出，由于缺乏功能性CLN3导致溶酶体膜上的转运缺陷是导致巴顿病的主要生化缺陷。
