This proposal is designed to investigate the role of individual NKA isoforms in vascular smooth muscle (VSM) function and metabolism. The NKA is composed of an alpha and beta subunit. The alpha subunit is the site of catalytic activity. Two isoforms of the alpha subunit are expressed in VSM (alpha1 and alpha2). In VSM, the NKA localizes to different regions of the cell surface in an isoform specific fashion. Individual isoforms appear to play different functional roles in VSM. The alpha1 subunit is thought to maintain basal membrane potential, whereas the alpha2 is thought to modulate contraction. Many disease states (ie. Diabetes, Hypertension) are known to adversely affect NKA function. However, the specific role of NKA isoforms is unclear due to the numerous complicating factors often associated with these conditions. NKA isoform levels will be altered by transgenic remodeling of the mouse genome in order to evaluate putative functional differences of the isoforms in the absence of complicating factors. A VSM promoter will be used to drive VSM specific overexpression of each subunit independently, generating at least two transgenic lines. We will determine the relationships between isoform expression, metabolism, and contractility in isolated VSM and their correlates of cardiovascular function and blood pressure in the whole animal.
