Demonstration of prostatic-type acid phosphatase in non-lysosomal granules in the crypt epithelium of the human duodenum

Abstract

Human prostatic-type of acid phosphatase has been demonstrated by biochemical methods to be expressed in a number of cells and tissues in addition to the prostate gland. However, the function of this activity is unknown, nor has the enzyme been convincingly localized at the cellular level in any non-prostatic tissues. Using biochemical and immunocytochemical methods, we demonstrate that human intestinal epithelium contains both a lysosomal and prostatic type of acid phosphatase. The prostatic-type enzyme is present only in the epithelium of the crypts and to a lesser extent in the transitional zone at the base of the villi, in contrast to the widely-distributed lysosomal type. The prostatic enzyme is contained in granules that do not react with anti-lysosomal acid phosphatase and are probably secretory in nature.

Cellular prostatic acid phosphatase, a PTEN-functional homologue in prostate epithelia, functions as a prostate-specific tumor suppressor

“…This precursor is posttranslationally modified into a mature 354 amino acid protein with a molecular weight of ~49 kDa by removing a 32 amino acid signal peptide at N-terminal [60,61]. The mature form of human PAcP is a 100 kDa glycoprotein containing two subunits of 50 kDa each with post-translational modifications, which is synthesized in the differentiated columnar epithelia of prostate gland [62–64]. The differential modifications result in two forms of the protein, the cellular and secretory form.…”