Department of Genomics and Proteomics, Advanced Science Research Center, Okayama University, Okayama 700–8530, Japan.
Biol Pharm Bull. 2010;33(11):1783-5. doi: 10.1248/bpb.33.1783.
Aspartate, an excitatory amino acid, is known to be stored in synaptic vesicles and exocytosed from some neurons to perform aspartergic neurotransmission. Through in vitro reconstitution, we found that sialin, a lysosomal sialic acid exporter, is responsible for the vesicular storage of aspartate in hippocampal neurons and pinealocytes. Mutations found in Salla disease cause decreased aspartate transport activity without affecting sialic acid transport. Thus, sialin is a multifunctional transporter. It is possible that people with Salla disease lose the ability of aspartergic neurotransmission, and this could explain why Salla disease involves severe neurological defects.
天冬氨酸是一种兴奋性氨基酸，已知储存在突触小泡中，并从一些神经元中排出，以执行天冬氨酸能神经传递。通过体外重组，我们发现唾液酸苷酶，一种溶酶体唾液酸输出载体，负责海马神经元和松果体细胞中天冬氨酸的囊泡储存。在 Salla 病中发现的突变导致天冬氨酸转运活性降低，而不影响唾液酸转运。因此，唾液酸苷酶是一种多功能转运体。患有 Salla 病的人可能失去天冬氨酸能神经传递的能力，这可以解释为什么 Salla 病涉及严重的神经缺陷。
