text: The DAG complex links the cytoskeleton to costameres to couple this multi-protein structure with the cell membrane.
full_question: The DAG complex links the cytoskeleton to costameres to couple this multi-protein structure with the cell membrane. CapZ localizes to a region of this structure with the help of nebulin, which also serves as a "molec- ular ruler." The poly-Ig chains and PEVK region motifs account for the differential elasticity of titin at various extensions of this structure, which may be represented on a force-length plot. At the center of this structure is a pale region named for the German word heller that contains the M-line. Intercalated discs are found at this structure's Z lines. It consists of thick and thin filaments that slide during contraction. For 10 points, name this basic myofibrillar structural unit of striated muscles that contains actin and myosin.
first_sentence: The DAG complex links the cytoskeleton to costameres to couple this multi-protein structure with the cell membrane.
raw_answer: sarcomeres [or Z line and Z disk until "extensions" is read; prompt on skeletal or cardiac muscle, myocytes, muscle cells, and cross-bridges; prompt on myofibrils, thin filaments, and thick filaments until they are read; do not accept "sacromeres"]