Communication among different cellular processes such as protein synthesis initiation and cell cycle inside mammalian cells are absolutely required to maintain viability of cells. Any miscommunication within these important cellular events may result in overload or lack thereof of un-translated messages in the cytoplasm and this may lead to abnormal phenotype such as cell death or apoptosis. Eukaryotic initiation factor 2 (eIF2)-associated glycoprotein, p67, whose human homolog is known as MetAP2 (Methionine aminopeptidase 2), regulates protein synthesis initiation by blocking the phosphorylation of the smallest α-subunit of eIF2 and cell cycle progression by inhibiting the activation and activity of extracellular signal-regulated kinases 1 and 2 (ERK1/2) mitogen-activated protein (MAP) kinases. Both ERK1/2 MAP kinases are highly activated in tumor cells and p67 inhibits this activation via direct binding to these kinases and thus shows tumor suppression activity. p67 has endopeptidase activity and it is involved in the regulation of phosphorylation of several kinases including eIF2α-specific kinases, ERK1/2 MAP kinases, and possibly several others. p67 uses its N-terminal 1-107 amino-acid-segment to block the phosphorylation site(s) of the targets or cleaves this segment auto-proteolytically that allows phosphorylation of the targets. Due to p67’s multifaceted activity in modulating functions of several kinases and possibly other proteins, it is involved in tumor suppression, differentiation of myoblasts, differentiation of cardiomyocytes, and in obesity.