Identification of a 48-kDa prenylated protein that associates with microtubules as 2',3'-cyclic nucleotide 3'-phosphodiesterase in FRTL-5 cells.

In an effort to study the nature of tubulin attachment to membranes, we have previously observed that after blocking prenylation in FRTL-5 thyroid cells, the microtubules become disconnected from the plasma membrane region [Bifulco M. et al. (1983) J. Cell. Physiol. 155, 340-348]. In this study we show that several [3H]mevalonate labeled proteins in FRTL-5 cells associate with membrane and cytoskeleton and, among these, we describe the presence of a 48-kDa prenylated protein, identified by immunoprecipitation as 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), that associates with microtubules. This latter association persists through several polymerization/depolymerization cycles, whereas other prenylated proteins are lost. It is suggested that CNP can be a novel microtubule-associated protein (MAP) and a promising candidate as a membrane anchor for microtubules.