Defining unique cardiac proteome: comparing sino-atrial node, atria, ventricle

心脏由不同类型的细胞组成，包括窦房结和收缩心肌。这些细胞类型之间的显著功能差异是由一个独特的蛋白质子集决定的，这些蛋白质组的鉴定将提供有关心脏功能如何执行和调节的重要信息。从分离的窦房结细胞、窦房结组织、右心房和左心室组织中提取蛋白质样本，进行双向凝胶电泳(pH 4~7和6~11；10%双Tris凝胶)。对600多个点进行了分析，得出了250种蛋白质的非冗余蛋白质清单，其中20种蛋白质是特定细胞类型的独特蛋白质。例如，一组钙处理蛋白，如Annexin A2、Annexin A4、Annexin A5，在窦房结中具有更高的丰度。它们可能在调节心跳方面发挥重要作用。神经丝3仅存在于窦房结，而不存在于心房和脑室。另一方面，I型胶原在心房肌中的丰度高于心室肌，但在窦房结细胞中不存在。根据相对量，很明显，细胞类型在指示表型功能需求的蛋白质类别中存在差异。

The heart is comprised of different cell types, including the sino-atrial node (SAN) and contractile myocardium. The substantial function difference between these cell types are dictated by a unique subset of proteins and that identification of these groups of proteins will provide important information on how heart function is performed and regulated. Protein samples were extracted from isolated SAN cells, SAN tissue, right atria and left ventricle tissues and subjected to 2-D gel electrophoresis (pH 4-7 and 6-11; 10% bis-TRIS gel). More than 600 spots were analyzed, producing a non-redundant protein list of 250 proteins, with 20 identified proteins unique for a specific cell type. For example, a group of calcium-handling proteins, such as annexin A2, annexin A4, annexin A5, have higher abundance in SAN. They may play important roles in regulating heart beat. Neurofilament 3 is present only in SAN and not in atria and ventricles. On the other hand, collagen 1 has higher abundance in atria than ventricle myocardium but is not present in the SAN cells. Based on relative quantities, it was clear that there are differences between the cell types in the protein classes indicating phenotypic functional requirements.