Tissue distribution and subcellular localization of a G-protein activated phosphoinositide 3-kinase. An immunohistochemical study.

We studied by light-and electron microscopic immunohistochemical techniques the anatomical distribution and subcellular localization of a G-protein activated phosphoinositide 3-kinase gamma (PI3Kgamma) in several tissues of rat, mouse, dog and man. Using monospecific polyclonal antisera and monoclonal antibodies to the enzyme protein PI3Kgamma immunoreactivity was detected in rat and mouse neutrophils, prostate, kidney, exocrine pancreas, salivary glands (parotid gland) as well as in dog and human exocrine pancreas and parotid gland. No immunoreactive material was found in Langerhans islet cells and in the nervous tissue. Fine structural analysis of PI3Kgamma immunoreactivity revealed immunolabeling of the basolateral membrane of rat kidney tubular cells and certain cells in the parenchyma of the glandular part of rat prostate gland. Our morphological data suggest a possible involvement of the enzyme in cellular transport phenomena and a regulatory influence in secretory processes.