Abstract
PLAC8 motif-containing proteins form a large family and members can be found in fungi, algae, higher plants and animals. They include the PCR proteins of plants. The name giving PLAC8 domain was originally found in a protein residing in the spongiotrophoblast layer of the placenta of mammals. A further motif found in a large number of these proteins including several PCR proteins is the CCXXXXCPC or CLXXXXCPC motif. Despite their wide distribution our knowledge about the function of these proteins is very limited. For most of them two membrane-spanning α-helices are predicted, indicating that they are membrane associated or membrane intrinsic proteins. In plants PLAC8 motif-containing proteins have been described to be implicated in two very different functions. On one hand, it has been shown that they are involved in the determination of fruit size and cell number. On the other hand, two members of this family, AtPCR1 and AtPCR2 play an important role in transport of heavy metals such as cadmium or zinc. Transport experiments and approaches to model the 3_D structure of these proteins indicate that they could act as transporters for these divalent cations by forming homomultimers. In this minireview we discuss the present knowledge about this protein family and try to give an outlook on how to integrate the different proposed functions into a common picture about the role of PLAC8 motif-containing proteins.
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References
Alpert, K.B., and Tanksley, S.D. (1996). High-resolution mapping and isolation of a yeast artificial chromosome contig containing fw2.2: a major fruit weight quantitative trait locus in tomato. Proc. Natl. Acad. Sci. USA 93, 15503–15507.
Arai, M., Mitsuke, H., Ikeda, M., Xia, J.X., Kikuchi, T., Satake, M., and Shimizu, T. (2004). ConPred II: a consensus prediction method for obtaining transmembrane topology models with high reliability. Nucleic Acids Res. 32, W390–W393.
Blaudez, D., Kohler, A., Martin, F., Sanders, D., and Chalot, M. (2003). Poplar metal tolerance protein 1 confers zinc tolerance and is an oligomeric vacuolar zinc transporter with an essential leucine zipper motif. Plant Cell 15, 2911–2928.
Bryan, J., and Aguilar-Bryan, L. (1999). Sulfonylurea receptors: ABC transporters that regulate ATP-sensitive K(+) channels. Biochim. Biophys. Acta 1461, 285–303.
Charron, J.B., Ouellet, F., Houde, M., and Sarhan, F. (2008). The plant apolipoprotein D ortholog protects Arabidopsis against oxidative stress. BMC Plant Biol. 8, 86.
Clemens, S. (2001). Developing tools for phytoremediation: towards a molecular understanding of plant metal tolerance and accumulation. Int. J. Occup. Med. Environ. Health 14, 235–239.
Clemens, S., Palmgren, M.G., and Krämer, U. (2002). A long way ahead: understanding and engineering plant metal accumulation. Trends Plant Sci. 7, 309–315.
Cobbett, C., and Goldsbrough, P. (2002). Phytochelatins and metallothioneins: Roles in heavy metal detoxification and homeostasis. Ann. Rev. Plant Biol. 53, 159–182.
Davletova, S., Rizhsky, L., Liang, H., Shengqiang, Z., Oliver, D.J., Coutu, J., Shulaev, V., Schlauch, K., and Mittler, R. (2005a). Cytosolic ascorbate peroxidase1 is a central component of the reactive oxygen gene network of Arabidopsis. Plant Cell 17, 268–281.
Frary, A., Nesbitt, T.C., Grandillo, S., Knaap, E., Cong, B., Liu, J., Meller, J., Elber, R., Alpert, K.B., and Tanksley, S.D. (2000). fw2.2: A quantitative trait locus key to the evolution of tomato fruit size. Science 289, 85–88.
Galaviz-Hernandez, C., Stagg, C., de Ridder, G., Tanaka, T.S., Ko, M.S., Schlessinger, D., and Nagaraja, R. (2003). Plac8 and Plac9, novel placental-enriched genes identified through microarray analysis. Gene 309, 81–89.
Gazzarrini, S., Kang, M., Abenavoli, A., Romani, G., Olivari, C., Gaslini, D., Ferrara, G., van Etten, J.L., Kreim, M., et al. (2009). Chlorella virus ATCV-1 encodes a functional potassium channel of 82 amino acids. Biochem. J. 420, 295–303.
Gustin, J.L., Loureiro, M.E., Kim, D., Na, G., Tikhonova, M., and Salt, D.E. (2009). MTP1-dependent Zn sequestration into shoot vacuoles suggests dual roles in Zn tolerance and accumulation in Zn hyperaccumulating plants. Plant J. 57, 1116–1127.
Guo, M., Rupe, M.A., Dieter, J.A., Zou, J., Spielbauer, D., Duncan, K.E., Howard, R.J., Hou, Z., and Simmons, C.R. (2010). Cell Number Regulator1 affects plant and organ size in maize: implications for crop yield enhancement and heterosis. Plant Cell 22, 1057–1073.
Hall, J.L. (2002). Cellular mechanisms for heavy metal detoxifycation and tolerance. J. Exp. Bot. 53, 1–11.
Hussain, D., Haydon, M.J., Wan, Y., Wong, E., Sherson, S.M., Young, J., Camakaris, J., Harper, J.F., and Cobbett, C.S. (2004). P-type ATPase heavy metal transporters with roles in essential zinc homeostasis in Arabidopsis. Plant Cell 16, 1327–1339.
Iomini, C., Li, L., Mo, W., Dutcher, S.K., and Piperno. G. (2006) Two flagellar genes, AGG2 and AGG3, mediate orientation to light in Chlamydomonas. Curr. Biol. 16, 1147–1153.
Korshunova, Y.O., Eide, D., Clark, W.G., Guerinot, M.L., and Pakrasi, H.B. (1999). The IRT1 protein from Arabidopsis thaliana is a metal transporter with a broad substrate range. Plant Mol. Biol. 40, 37–44.
Krämer, U., and Clemens, S. (2006). Functions and homeostasis of zinc, copper, and nickel in plants. In Molecular Biology of Metal Homeostasis and Detoxification from Microbes to Man, M.J. Tamás, and E. Martinoia, eds. (Berlin, Germany: Springer), pp. 214–272.
Lane, T.W., Saito, M.A., George, G.N., Pickering, I.J., Prince, R.C., and Morel, F.M. (2005). Biochemistry: a cadmium enzyme from a marine diatom. Nature 435, 42.
Li, Z.S., Lu, Y.P., Zhen, R.G., Szczypka, M., Thiele, D.J., and Rea, P.A. (1997). A new pathway for vacuolar cadmium sequestration in Saccharomyces cerevisiae: YCF1-catalyzed transport of bis(glutathionato)cadmium. Proc. Natl. Acad. Sci. USA 94, 42–47.
Luhua, S., Ciftci-Yimaz, S., Harpr, J., Cushman, J., and Mittler, R. (2008) Enhanced tolerance to oxidative stress in transgenic Arabidopsis plants expressing proteins of unknown function. Plant Physiol. 148, 280–292
Marschner, H. (1995). Mineral Nutrition of Higher Plants. (San Diego: Academic Press).
Nakagawa, Y., Katagiri, T., Shinozaki, K., Qi, Z., Tatsumi, H., Furuichi, T., Kishigami, A., Sokabe, M., Kojima, I., Sato, S., et al. (2007). Arabidopsis plasma membrane protein crucial for Ca2+ influx and touch sensing in roots. Proc. Natl. Acad. Sci. USA 104, 3639–3644.
Ortiz, D.F., Ruscitti, T., McCue, K.F., and Ow, D.W. (1995) Transport of metal-binding peptides by HMT1, a fission yeast ABCtype vacuolar membrane protein. J. Biol. Chem. 270, 4721–4728.
Payandeh, J., and Pai, E.F. (2006). A structural basis for Mg2+ homeostasis and the CorA translocation cycle. EMBO J. 25, 3762–3773.
Snavely, M.D., Florer, J.B., Miller, C.G., and Maguire, M.E. (1989). Magnesium transport in Salmonella typhimurium: 28Mg2+ transport by the CorA, MgtA, and MgtB systems. J. Bacteriol. 171, 4761–4766.
Song, W.Y., Martinoia, E., Lee, J., Kim, D., Kim, D.Y., Vogt, E., Shim, D., Choi, K.S., Hwang, I., and Lee, Y. (2004). A novel family of cys-rich membrane proteins mediates cadmium resistance in Arabidopsis. Plant Physiol.135, 1027–1039.
Song, W.Y., Choi, K.S., Kim, D.Y., Geisler, M., Park, J., Vincenzetti, V., Schellenberg, M., Kim, S.H., Lim, Y.P., Noh, E.W., et al. (2010). Arabidopsis PCR2 is a zinc exporter involved in both zinc extrusion and long-distance zinc transport. Plant Cell 22, 2237–2252.
Van der Zaal, B.J., Neuteboom, L.W., Pinas, J.E., Chardonnens, A.N., Schat, H., Verkleij, J.A.C., and Hooykaas, P.J.J. (1999). Overexpression of a novel Arabidopsis gene related to putative zinc-transporter genes from animals can lead to enhanced zinc resistance and accumulation. Plant Physiol. 119, 1047–1056.
Voelker, C., Schmidt, D., Mueller-Roeber, B., and Czempinski, K. (2006). Members of the Arabidopsis AtTPK/KCO family form homomeric vacuolar channels in planta. Plant J. 48, 296–306.
Wintz, H., Fox, T, Wu, Y.Y., Feng, V., Chen, W., Chang, H.S., Zhu, T., and Vulpe, C. (2003). Expression profiles of Arabidopsis thaliana in mineral deficiencies reveal novel transporters involved in metal homeostasis. J. Biol. Chem. 278, 47644–47653.
Worlock, A.J., and Smith, R.L. (2002). ZntB is a novel Zn2+ transporter in Salmonella enterica serovar Typhimurium. J. Bacteriol. 184, 4369–4373.
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Song, WY., Hörtensteiner, S., Tomioka, R. et al. Common functions or only phylogenetically related? The large family of PLAC8 motif-containing/PCR genes. Mol Cells 31, 1–7 (2011). https://doi.org/10.1007/s10059-011-0024-8
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DOI: https://doi.org/10.1007/s10059-011-0024-8