期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1998
卷号：95
期号：14
页码：8351-8356
DOI：10.1073/pnas.95.14.8351
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：p70 S6 kinase (p70S6k) is a mitogen-activated protein kinase that plays a central role in the control of mRNA translation. It physiologically phosphorylates the S6 protein of the 40s ribosomal subunit in response to mitogenic stimuli and is a downstream component of the rapamycin-sensitive pathway, which includes the 12-kDa FK506 binding protein and includes rapamycin and the 12-kDa FK506 binding protein target 1. Here, we report the identification of neurabin (neural tissue-specific F-actin binding protein), a neuronally enriched protein of 1,095 amino acids that contains a PDZ domain and binds p70S6k. We demonstrate the neurabin-p70S6k interaction by yeast two-hybrid analysis and biochemical techniques. p70S6k and neurabin coimmunoprecipitate from transfected HEK293 cells. Site-directed mutagenesis of neurabin implicates its PDZ domain in the interaction with p70S6k, and deletion of the carboxyl-terminal five amino acids of p70S6k abrogates the interaction. Cotransfection of neurabin in HEK293 cells activates p70S6k kinase activity. The mRNA of neurabin and p70S6k show striking colocalization in brain sections by in situ hybridization. Subcellular fractionation of rat brain demonstrates that neurabin and p70S6k both localize to the soluble fraction of synaptosomes. By way of its PDZ domain, the neuronal-specific neurabin may target p70S6k to nerve terminals.
