ABSTRACT
Similar to cardiac myocytes and skeletal muscle myocytes, VSMCs share the ability to undergo hypertrophy under certain conditions including hypertension. Importantly, hypertrophic factors utilize common signal transduction pathways in VSMCs. Generally, hypertrophy is induced by a progression of cellular protein synthesis. In the signaling pathway of protein synthesis in VSMCs, phosphatidylinositol 3-kinase (PI3-K), Akt/protein kinase B (PKB), and p70 S6 kinase (p70S6K) play an important role.6
Phosphorylation and activation of Akt/PKB is catalyzed by phosphatidylinositol (3,4,5)-trisphosphate (PIP3)-dependent protein kinase-1 (PDK-1). PIP3 is the product of the reaction catalyzed by PI3-K. Activation of Akt/PKB leads to p70S6K activation in VSMCs7
p70S6K phosphorylates the ribosomal protein S6 and thereby participates in the translation of a class of mRNA transcripts which contain an oligopyrimidine tract at their transcriptional start site. In addition, regulation of eIF4E (eukaryotic initiation factor-4E)
