The actin-binding proteins adseverin and gelsolin are both highly expressed but differentially localized in kidney and intestine

To understand the distinct functions of the closely related actin-severing proteins adseverin and gelsolin, we examined the expression of these protei ns in detail during mouse and human development using a new highly sensitiv e and specific set of antibody reagents. Immunoblot analysis demonstrated t hat adseverin was highly expressed in mouse kidney and intestine at all sta ges of development and in human fetal and adult kidney. In contrast and as reported previously, gelsolin was expressed much more widely in both murine and human tissues, Immunohistochemistry on murine kidney sections revealed a predominantly dif ferential localization of adseverin and gelsolin, Adseverin was expressed i n peripolar cells, thin limbs, thick ascending limbs, and principal cells o f cortical and medullary collecting ducts where it was diffusely localized in the cytoplasm, Gelsolin was expressed in the distal convoluted tubule, i ntercalated cells and principal cells of cortical and medullary collecting ducts, and in ureter, In the distal convoluted tubule, gelsolin showed a di ffuse distribution and in principal cells of collecting ducts a localizatio n at the basolateral pole, In intercalated cells, gelsolin localization was heterogeneous, either at the apical pole or diffusely in the cytoplasm, In human fetal and adult kidney, adseverin was expressed only in collecting d ucts whereas gelsolin was expressed in thick ascending limbs and collecting ducts. In mouse and human intestine adseverin was expressed in enterocytes with a gradient of increasing expression from the duodenum to the colon, and from the crypt to the villus, The observations indicate high level expression of adseverin in specific cells of the kidney and colon, and suggest a previou sly unrecognized function of adseverin in epithelial cell function.