(A) Flowchart for the selection of candidate genes. (B) The relative expression levels of 75678_at correlated well with the relative PAP values in the respective patients. (C) Tissue localization of the candidate gene expression was analyzed using the GeneExpress database; 75678_at was specifically expressed in the heart. (D) Each MLCK family member possesses a highly conserved serine-threonine kinase domain in the C-terminal region of the protein. Amino acid residues on black backgrounds are the most commonly conserved residues at each position; residues on gray backgrounds are similar to the consensus amino acids. (E) Expression analysis of MLCK family members using multiple human tissue Northern blot membranes. The 2 transcripts transcribed from MYLK (encoding smMLCK) were ubiquitously expressed with the exception of skeletal muscle, thymus, and peripheral blood leukocytes. In contrast, MYLK2 (encoding skMLCK) and MYLK3 (encoding cardiac-MLCK) were only expressed in skeletal muscle and heart, respectively. (F) Fluorescence microscopy of cardiomyocytes cultured in serum-free conditions and infected with adenovirus encoding LacZ (Ad-LacZ) revealed predominantly round-shaped cells with disorganized sarcomere structures. Infection with adenovirus encoding cardiac-MLCK (Ad-cMK) at a MOI of 120 increased the number of the cells with organized sarcomere structures. Original magnification, ×1,000. (G) The percentage of cells with organized sarcomeres was significantly higher in cardiomyocytes infected with adenovirus encoding cardiac-MLCK than in those infected with adenovirus encoding LacZ. Values are mean ± SEM. *P < 0.001.