Desmin-Membrane Interactions in Skeletal Muscle

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; R o o t E n t r y F @ C o m p O b j b W o r d D o c u m e n t O b j e c t P o o l . / 0 1 2 3 4 5 6 7 8 F Microsoft Word 6.0 Document MSWordDoc Word.Document.6 ; 9418715 Kymkowsky In vertebrate embryos, blocks of skeletal muscle cells are attached to one another through a specialized junction, known as the intersomite junction. This junction is structurally and functionally similar to the junction that connects muscle to tendon and bone in adult animals. Desmin-type intermediate filaments are structural components of muscle cells and are found concentrated at the intersomite junction. Studies from our lab indicate that desmin filaments play a critical role in maintaining the attachment of myofibrils to the muscle cell membrane at the intersomite junction. Although it is clear that desmin can interact with the muscle cell membrane, the molecules involved in this interaction are unknown. In the course of previous NSF funded work, we used the frog Xenopus to study the organization of desmin. We determined the N-terminal head region of desmin mediates the interaction between desmin and the muscle cell membrane. In the studies proposed here we will attempt to identify muscle membrane proteins that bind desmin. We will use the recently devised, and high ly sensitive, yeast two-hybrid system. In these studies, the head domain of desmin will be used to screen a cDNA library enriched in muscle components. cDNA isolated in this screen will be characterized to determine whether they are in fact expressed in the muscle cells of the early embryo. Proteins that they encode will be studies to determine their localization and function. %%% To carry out their mechanical functions intermediate filaments generally must interact with membranes. Yet, the molecular details of intermediate filament-membrane interactions are poorly understood. By identifying proteins that mediate the interaction of desmin filaments with muscle cell membranes, we will be able to define, at the molecular level, interactions critical to normal muscle cell organization and function. *** ; Oh +' 0 $ H l D h S u m m a r y I n f o r m a t i o n ( - R:\WWUSER\TEMPLATE\NORMAL.DOT 9418715 Shirley Parker Shirley Parker @ E @ @ E @ F # Microsoft Word 6.0 1 ; ; e 3 e j j j j j j j @ 1 " q T 7 @ j @ j j j j ~ j j j j : 9418715 Kymkowsky In vertebrate embryos, blocks of skeletal muscle cells are attached to one another through a specialized junction, known as the intersomite junction. This junction is structurally and functionally similar to the junction that connects muscle to tendon and bone in adult animals. Desmin-type intermediate filaments are structural components of muscle cells and are found concentrated at the intersomite junction. Studies from our lab indicate that desmin filaments play a critical role in maintaining the attachment of myofibrils to the muscle cell mem