In most eukaryotic cells, chromosome stability is maintained in part by the action of telomerase, an enzyme that synthesizes DNA repeats at the termini of chromosomes. Seimiya et al. report that regulation of telomerase activity may be achieved by controlling its access to DNA in the nucleus. The catalytic subunit of telomerase, TERT, is associated with 14-3-3, an accessory protein involved in signaling pathways that control cell proliferation, apoptosis, and cell-cycle progression. Mutagenesis indicates that a putative amphipathic helix at the COOH-terminus of TERT interacts with 14-3-3. The authors propose that this interaction may mask a nuclear export signal in TERT and, thus, prevent its interaction with nuclear export machinery. The interaction suggests a link between telomerase function and signal transduction machinery that regulates other cellular processes.
Seimiya, H., Sawada, H., Muramatsu, Y., Shimizu, M., Ohko, K., Yamane, K., and Tsuro, T. (2000) Involvement of 14-3-3 proteins in nuclear localization of telomerase. EMBO J. 19: 2652-2661. [Abstract] [Full Text]