title: Atrial chamber-specific expression of sarcolipin is regulated during development and hypertrophic remodeling.
abstract: Intracellular Ca2+ regulation is critical in the normal cardiac function and development of pathologic hearts. Phospholamban, an endogenous inhibitor of sarcoplasmic reticulum Ca2+ ATPase in the sarcoplasmic reticulum, plays an important role in Ca2+ cycling in heart. Recently, sarcolipin has been identified as having a similar function as phospholamban in skeletal muscle. Because phospholamban is differentially expressed in atrial and ventricular myocardia and its expression is often altered in diseased hearts, we investigated the cardiac chamber specificity of sarcolipin expression and its regulation during development and hypertrophic remodeling. Northern blot analysis revealed that the expression of mouse sarcolipin mRNA was most abundant in the atria and was undetectable in the ventricles, indicating an atrial chamber-specific expression pattern. Atrial chamber-specific expression of sarcolipin mRNA was increased during development. These findings were confirmed by in situ hybridization studies. In addition, sarcolipin expression was down-regulated in the atria of hypertrophic heart when induced by ventricular specific overexpression of the activated H-ras gene. In humans, sarcolipin mRNA was also expressed in the atria but not detected in the ventricles, although sarcolipin expression was most abundant in skeletal muscle. Taken together, sarcolipin is likely to be an atrial chamber-specific regulator of Ca2+ cycling in heart.
authors.affiliation: Department of Pediatric Cardiology, Institute of Advanced Biomedical Engineering and Science, Graduate School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan. sminamis@med.yokohama-cu.ac.jp
authors.forename: Susumu
authors.initials: S
authors.lastname: Minamisawa
authors.forename: Yibin
authors.initials: Y
authors.lastname: Wang
authors.forename: Ju
authors.initials: J
authors.lastname: Chen
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Chien
authors.forename: Rumiko
authors.initials: R
authors.lastname: Matsuoka
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D006325:Heart Atria / Q000196:embryology; D006801:Humans; D006984:Hypertrophy; D017403:In Situ Hybridization; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D008822:Mice, Transgenic; D009124:Muscle Proteins / Q000096:biosynthesis*; D011510:Proteolipids / Q000096:biosynthesis*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D013997:Time Factors; D014018:Tissue Distribution; D015854:Up-Regulation; D000099211:Phospholamban
chemical_list: D002118:Calcium; D002135:Calcium-Binding Proteins; D000252:Calcium-Transporting ATPases; D018076:DNA, Complementary; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D009124:Muscle Proteins; D011510:Proteolipids; D012313:RNA; D012333:RNA, Messenger; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000099211:Phospholamban; C077258:sarcolipin