Cleavage of α-sunuclein by Neurosin (Kallikrein-6)

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 16590840
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Neurology
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: MIZUNO Toshiki Kyoto Prefectural University of Medicine, medical department, Associate Professor, 医学研究科, 助教授 (30264782)
• Co-Investigator(Kenkyū-buntansha): YAMAGUCHI Nozomi Kyoto Prefectural University of Medicine, medical department, Associate Professor, 医学研究科, 助教授 (40079752) ; NAKAGAWA Masanori Kyoto Prefectural University of Medicine, medical department, Professor, 医学研究科, 教授 (50198040)
• Project Period (FY): 2004 – 2005
• Keywords: Neurosin / α-synuclein / serine protease / NAC domain

Research Abstract

Background : Neurosin (Kallikrein-6), one of the serine proteases predominantly expressed in the central nervous system, was reported to be possible to degrade α-synuclein, a key protein for Parkinson disease. However, cleavage site of α-synuclein by neurosin has not been detected. In this study, cleavage sites of α-synuclein were identified by LC/MS/MS.
Method : Degradations of wild and mutant α-synuclein by neurosin were evaluated semi-quantitatively by SDS-PAGE. Restricted fragments of α-synuclein cleaved by neurosin were examined by LC/MS/MS (Ion trap mass spectrometer ; LCQ Advatage, Themo Electron Corporation, Waltham, MA).
Results : The first cleaving site of α-synuclein was Lyn80, and secondly Lyn96, Lyn97, Asp115 and Asp121 were cleaved by neurosin. A30P mutant α-synuclein was degraded slower than wild α-synuclein by neurosin.
Interpretation : The dominant cleaving site of Lyn80 is the center of the NAC region, which is responsible for polymerization of the α-synuclein. Our results showed that neurosin can degrade α-synuclein and it may inhibit the polymerization of α-synuclein by cleaving the NAC region.