A One-sided View of Kinetochore Attachment in MeiosisReferences1030 Cell 126, September 22, 2006 ©2006 Elsevier Inc.somes are needed for IL-1β matura-tion, whereas others are involved in caspase-1-dependent cell death. Would some inflammasomes activate caspase-1 more efficiently than oth-ers? Or do certain complexes inhibit the secretion of active caspase-1 to the extracellular space? Do higher levels of active caspase-1 inside the cell result in a broader spectrum of substrate processing, leading to apoptosis? Finally, during infections, how much can lipids protect us? The authors show that, when using live bacteria instead of pure recombinant pore-forming toxins, cells underwent apoptosis, albeit at lower levels than when lipid metabolism was blocked by an inhibitor of SREBP activa-tion. Do lipids slow down the death caused by invading pathogens and provide the cell with a survival win-dow, giving it time to secrete proin-flammatory cytokines, repair itself, and resist the infection? And is it only when the infection is persistent that the cell maintains caspase-1 in a hyperactivated state and commits suicide? Answering these questions will significantly enhance our under-standing of the multifaceted roles of caspase-1 in host defense.RefeRencesFranchi, L., Amer, A., Body-Malapel, M., Kan-neganti, T.D., Ozoren, N., Jagirdar, R., Inohara, N., Vandenabeele, P., Bertin, J., Coyle, A., et al. (2006). Nat. Immunol. 7, 576–582.Gurcel, L., Abrami, L., Girardin, S., Tschopp, J., and van der Goot, F.G. (2006). Cell, this is-sue.Kanneganti, T.D., Ozoren, N., Body-Malapel, M., Amer, A., Park, J.H., Franchi, L., Whitfield, J., Barchet, W., Colonna, M., Vandenabeele, P., et al. (2006). Nature 440, 233–236.Kuranaga, E., Kanuka, H., Tonoki, A., Takemo-to, K., Tomioka, T., Kobayashi, M., Hayashi, S., and Miura, M. (2006). Cell 126, 583–596.Launay, S., Hermine, O., Fontenay, M., Kro-emer, G., Solary, E., and Garrido, C. (2005). Oncogene 24, 5137–5148.Mariathasan, S., Weiss, D.S., Newton, K., McBride, J., O’Rourke, K., Roose-Girma, M., Lee, W.P., Weinrauch, Y., Monack, D.M., and Dixit, V.M. (2006). Nature 440, 228–232.Martinon, F., Petrilli, V., Mayor, A., Tardivel, A., and Tschopp, J. (2006). Nature 440, 237–241.Miao, E.A., Alpuche-Aranda, C.M., Dors, M., Clark, A.E., Bader, M.W., Miller, S.I., and Ader-em, A. (2006). Nat. Immunol. 7, 569–575.Molofsky, A.B., Byrne, B.G., Whitfield, N.N., Madigan, C.A., Fuse, E.T., Tateda, K., and Swanson, M.S. (2006). J. Exp. Med. 203, 1093–1104.Ren, T., Zamboni, D.S., Roy, C.R., Dietrich, W.F., and Vance, R.E. (2006). PLoS Pathog. 2, e18.When proliferating cells divide, k i n e t o c h o r e s — p r o t e i n a c e o u s structures that form on the cen-tromeres of sister chromatids—are captured by microtubules emanat-ing from both spindle poles (bipolar attachment). This bipolar attach-ment ensures that sister chroma-tids are faithfully segregated to daughter cells: a process called equational division (Figure 1). Dur-ing meiosis, however, one round of DNA replication is followed by two rounds of cell division, which results in four daughter cells, each with half the number of chromo-somes. The first round of cell divi-sion, meiosis I, is characterized by the fact that homologous chro-mosomes, and not sister chroma-tids (that are observed in mitosis and meiosis II), are segregated to opposite poles of the spindle. During this “reductional” division, sister kinetochores are always attached by spindle microtubules that originate from the same pole (monopolar attachment; Figure 1). A key question that remains is how monopolar attachment occurs at the kinetochore in meiosis I. In this issue of Cell, Petronczki et al. (2006) address this question A One-sided View of Kinetochore Attachment in MeiosisYoshinori Watanabe1,*1Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan*Contact: [email protected] 10.1016/j.cell.2006.09.005Meiosis includes a reductional division in which homologous chromosomes, rather than sister chromatids, are segregated to opposite poles of the spindle. In this issue of Cell, Petronczki et al. (2006) report that casein kinase 1 contributes to this process by promoting the attachment of both kinetochores of a homolog to only one pole of the meiotic spindle in budding yeast.Cell 126, September 22, 2006 ©2006 Elsevier Inc. 1031and identify a protein that is important for monopo-lar attachment in budding yeast Saccharomyces cer-evisiae.The regulation of kineto-chore orientation and attach-ment to microtubules is strictly regulated during mitotic divi-sion, which is considered the “prototype” of chromo-some segregation. One of the crucial mechanisms at work is the stabilization of ki n etoch o re - mi c r ot ub u le attachment through tension. Unstable spindle microtubules repeatedly attach and release kinetochores until