Figure 4.

Effect of sgk2 on the degradation of cell surface hOAT1. (A) COS-7 cells were co-transfected with hOAT1 and control vector or with hOAT1 and the constitutive active form of sgk2 (CA-sgk2). The degradation of cell surface hOAT1 was then analyzed as described in “Materials and Methods” section followed by immunoblotting (IB) using anti-myc antibody. (B) Densitometry plot of results from (A) as well as from other repeat experiments. The amount of undegraded cell surface hOAT1 was expressed as % of total initial cell surface hOAT1 pool. Values are mean ± S.E. (n = 3). (C) Total expression of sgk2 and house-keeping protein β-actin. COS-7 cells were co-transfected with hOAT1 and control vector or with hOAT1 and the constitutive active form of sgk2 (CA-sgk2). Transfected cells were lysed, followed by immunoblotting (IB) with anti-sgk2 antibody (top panel) or anti-β-actin antibody (bottom panel).