Leucine-rich glioma inactivated 3 associates with syntaxin 1.

Abstract

Leucine-rich glioma inactivated 3 (LGI3) is a member of LGI/epitempin (EPTP) family. The biological function of LGI3 and its association with disease are not known. We previously reported that mouse LGI3 was highly expressed in brain in a developmentally and transcriptionally regulated manner. In this study, we identified syntaxin 1, a SNARE component in exocytosis, as a candidate functional target of LGI3. Western blot analysis of mouse brain extract with LGI3 antibodies detected multiple protein forms (75-, 60-, 35- and 25-kDa). Proteomic analysis, pull-down and coimmunoprecipitation experiments identified syntaxin 1 as an LGI3-associated protein. LGI3 colocalized with syntaxin 1 in processes of cortical neurons with punctate synaptic pattern and was enriched in synaptosomal fraction. Coimmunoprecipitation showed that LGI3-syntaxin 1 complex did not contain other SNARE components, SNAP25 and VAMP2. Recombinant LGI3 attenuated Ca(2+)-evoked glutamate release from digitonin-permeabilized synaptosomes and transfection of PC12 cells with LGI3 decreased K(+)-induced secretion of human growth hormone. Thus, LGI3 may play a regulatory role in neuronal exocytosis via its interaction with syntaxin 1.

• Authors: Woo-Jae Park, Sang Eun Lee, Nyoun Soo Kwon, Kwang Jin Baek, Dong-Seok Kim, Hye-Young Yun
• Journal: Neuroscience letters (Neurosci Lett) Vol. 444 Issue 3 Pg. 240-4 (Oct 31 2008) ISSN: 0304-3940 [Print] Ireland
• PMID: 18760330 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• LGI3 protein, mouse
• Nerve Tissue Proteins
• Recombinant Proteins
• Syntaxin 1
• Human Growth Hormone
• Glutamic Acid
• Calcium

Topics

• Animals
• Calcium (metabolism)
• Cells, Cultured
• Exocytosis (physiology)
• Glutamic Acid (metabolism)
• Human Growth Hormone (genetics, metabolism)
• Humans
• Mice
• Mice, Inbred C57BL
• Nerve Tissue Proteins (genetics, metabolism)
• Neurons (metabolism)
• Rats
• Recombinant Proteins (metabolism)
• Synaptosomes (metabolism)
• Syntaxin 1 (metabolism)
• Transfection