Definition and expression in E. coli of large fragments from the human lipid kinase phosphatidylinositol 4-kinase type III alpha, and purification of a 1100-residue N-terminal module

摘要

The eukaryotic lipid kinase phosphatidylinositol 4-kinase III alpha (PI4KA in higher eukaryotes) is a ubiquitous enzyme that synthesizes the plasma membrane pool of phosphatidylinositol 4-phosphate. This important phosphoinositide has key roles in different signalization pathways, vesicular traffic and cellular compartment identity. Moreover, human PI4K4A is an essential factor for hepatitis C virus replication. PI4KA is a large protein (2102 residues for human PI4KA) with the kinase domain making up the ca 400 C-terminal residues. There is essentially no structural information about the 1500 N-terminal residues and no clue as to the function of most of this region of PI4KA.