Serum Level Assay And Functional Study Of A Cardiac-specific Kinase P93

A novel kinase gene p93 (GenBank Accession No.AF116826) was isolated from human adult heart cDNA libraries based on large-scale ESTs (Expressed Sequence Tags) sequencing. Bioinformatics assay clarified that it was localized on 1p31-p21, a critical region for atrioventricular septal defect. The full-length cDNA of this clone is 3420 bp and contains a continuous open reading frame (ORF) of 2505 bp, which encodes a protein of 835 amino acids. The molecular weight of this protein is predicted 93 KD and was named p93, which contains three kinds of protein domains: seven ankyrin repeats (ANK) in N-terminal followed by a protein kinase (PK) domain and a C-teiminal Serine-rich (Ser-rich) domain. Phylogenetic parsimony analysis indicated that p93 belongs to the MLK family. Northern blot using six-fetal and eight-adult tissues and 76-tissue array analysis demonstrated that p93 is expressed in fetal and adult heart, which suggested p93 is virtually cardiac-specific. Heart immunohistochemistry with special monoclonal antibody revealed that p93 is only expressed in embryonic and adult cardiac myocytes. Additionally, p93 could perform autophosphorylation was showed by kinase activity assay in vitro.A great deal pre-work indicated that p93, as a novel cardiac-specific protein kinase, has close relationship with the development of heart and the cardiomyopathy. But there is still no direct clinical evidence to prove the relationship between the p93 and the...