Identification of a factor Xa-interactive site within residues 337-372 of the factor VIII heavy chain.

We recently demonstrated that the residues 337-372, comprising the acidic C-terminal region in A1 subunit, interact with factor Xa during the proteolytic inactivation of factor VIIIa (Nogami, K., Wakabayashi, H., and Fay, P.

Peptide ligands in antibacterial drug discovery: use as inhibitors in target validation and target-based screening.

There is an urgent need to develop novel classes of antibiotics to counter the inexorable rise of resistant bacterial pathogens. Modern antibacterial drug discovery is focused on the identification and validation of novel protein targets that may have a suitable therapeutic index. In combination with assays for function, the advent of microbial genomics has been invaluable in identifying novel antibacterial drug targets.

Interaction of the A1 subunit of factor VIIIa and the serine protease domain of factor X identified by zero-length cross-linking.

We have previously used a solid phase binding assay to localize a Factor X (FX) interactive site to the acidic C-terminus of the A1 subunit of FVIIIa (Lapan KA, Fay PJ. J Biol Chem 1997; 272: 2082-2088). The complex of FVIII-FX was made covalent following reaction with the zero-length cross-linking reagent 1-ethyl-3-(3dimethylaminopropyl-)carbodiimide hydrochloride (EDC).

Localization of a factor X interactive site in the A1 subunit of factor VIIIa.

The protein cofactor, factor (F) VIIIa, is required for the efficient conversion of the substrate FX to FXa by the serine protease FIXa. The interaction between human FVIII (and its constituent subunits) and FX was characterized using a solid phase binding assay performed in the absence of phospholipid and FIXa. Saturable binding of FX to heterodimeric FVIII, the FVIII heavy chain (contiguous A1-A2 domains), the FVIIIa-derived A1/A3-C1-C2 dimer, and the isolated A1 subunit was observed with estimated Kd values ranging from approximately 1 to 3 microM.

Expression of the C terminus of the amyloid precursor protein alters growth factor responsiveness in stably transfected PC12 cells.

The amyloid precursor protein (APP) is a molecule centrally involved in Alzheimer disease pathology, but whose normal function is still poorly understood. To investigate the consequences of increased intracellular production of various regions of APP on cellular physiology, we stably transfected PC12 cells with the C-terminal 100 amino acids of the human APP. In eight transfected clones that express the APP(C100) protein, exposure to nerve growth factor (NGF) did not promote differentiation.