tailieunhanh - Báo cáo khoa học: Calpain 1–titin interactions concentrate calpain 1 in the Z-band edges and in the N2-line region within the skeletal myofibril

Calpain 1, a ubiquitous calcium-dependent intracellular protease, was recently found in a tight association with myofibrils in skeletal muscle tis-sue [Delgado EF, Geesink GH, Marchello JA, Goll DE & Koohmaraie M (2001) J Anim Sci79, 2097–2107). Our immunofluorescence and immuno-electron microscopy investigations restrain the protease location at the per-iphery of the Z-band and at the midpoint of the I-band. | iFEBS Journal Calpain 1-titin interactions concentrate calpain 1 in the Z-band edges and in the N2-line region within the skeletal myofibril Fabrice Raynaud1 Eric Fernandez2 Gerald Coulis2 Laurent Aubry2 Xavier Vignon3 Nathalie Bleimling4 Mathias Gautel5 Yves Benyamin1 and Ahmed Ouali2 1 Cell Motility Laboratory EPHE UMR-5539 UM2 Montpellier France 2 Muscle Biochemistry Group INRA-Theix Saint Genes Champanelle France 3 UMR-DevelopmentalBiology and Biotechnology INRA Jouy en Josas France 4 Max-Planck-Institut fur Molekulare Physiologie Abt. Physikalische Biochemie Dortmund Germany 5 Muscle Cell Biology The RandallCentre New Hunt s House King s College London Guy s Campus London UK Keywords calcium calpain proteolysis sarcomere titin Correspondence Y. Benyamin UMR 5539 CC 07 UM2 Place E. Bataillon 34 090 Montpellier France Fax 33 4 67144927 Tel 33 4 67143813 E-mail benyamin@ Received 13 January 2005 revised 22 March 2005 accepted 23 March 2005 doi Calpain 1 a ubiquitous calcium-dependent intracellular protease was recently found in a tight association with myofibrils in skeletal muscle tissue Delgado EF Geesink GH Marchello JA Goll DE Koohmaraie M 2001 J Anim Sci 79 2097-2107 . Our immunofluorescence and immunoelectron microscopy investigations restrain the protease location at the periphery of the Z-band and at the midpoint of the I-band. Furthermore calpain 1 is found to localize in myofibril fractures described as proteolysis sites in postmortem bovine skeletal red muscles near the calcium deposits located at the N1 and N2 level. This in situ localization of calpain 1 is substantiated by binding assays with two titin regions covering the I-band region a native fragment of 150 kDa identified by mass spectrometry that includes the N-terminal Z8-I5 region and the N1-line region of titin and an 800 kDa fragment external to the N1 line that bears the PEVK N2 region. These two titin fragments are shown to tightly bind .