The RASSF proteins are a family of polypeptides, each containing a conserved Ras association domain, suggesting that these scaffold proteins may be effectors of activated Ras or Ras-related small GTPases. RASSF proteins are characterized by their ability to inhibit cell growth and proliferation while promoting cell death. RASSF1 isoform A is an established tumor suppressor and is frequently silenced in a variety of tumors and human cancer cell lines. However, our understanding of its function in terminally differentiated cell types, such as cardiac myocytes, is relatively nascent. Herein, we review the role of RASSF1A in cardiac physiology and disease and highlight signaling pathways that mediate its function. 1. Introduction The Ras association domain family (RASSF) consists of 10 members: RASSF1-10. Additionally, splice variants of RASSF1, 5 and 6 have been identified [1]. Importantly, all isoforms contain a Ras association (RA) domain either in their C-terminal (RASSF1-6) or N-terminal (RASSF7-10) regions [2]. To date, no known catalytic activity has been described for this family, and the general consensus supposes that RASSF proteins function as scaffolds to localize signaling in the cell. Accordingly, protein-protein interactions are critical in mediating their biological functions. RASSF1 isoform A (RASSF1A) is the most characterized member of the RASSF family. This paper will focus primarily on RASSF1A and its role in cardiovascular biology. 2. RASSF1A RASSF1A was first identified and described by Dammann et al. in 2000 [3]. The RASSF1 gene encodes multiple splice variants, including the two predominant isoforms, RASSF1A and C. The RASSF1A isoform is the longest variant of the RASSF1 gene. Structurally, RASSF1A is a product of exons 1α, 2α/β, 3, 4, 5, and 6, while RASSF1C consists of exons 2γ, 3, 4, 5, and 6. Both isoforms contain a C-terminal RA domain; however, RASSF1A has an additional C1 domain that is not present in RASSF1C. The RASSF1 gene is located on Chr3p21.3 [3]. This short arm of chromosome 3 is known to exhibit loss of heterozygosity in many tumor models and is thought to harbor tumor suppressor genes. As the literature has shown, RASSF1A fits this description. The RASSF1A promoter contains a CpG island that shows a high frequency of hypermethylation in tumors, thereby silencing RASSF1A expression in many human cancers including lung, breast, ovarian, renal, and bladder [4–7]. RASSF1A expression is also lost in numerous cancer cell lines, while RASSF1C expression is seemingly unaffected [4]. Interestingly, recent work suggests that
References
[1]
M. Gordon and S. Baksh, “RASSF1A: not a prototypical Ras effector,” Small GTPases, vol. 2, no. 3, pp. 148–157, 2011.
[2]
J. Avruch, R. Xavier, N. Bardeesy et al., “Rassf family of tumor suppressor polypeptides,” Journal of Biological Chemistry, vol. 284, no. 17, pp. 11001–11005, 2009.
[3]
R. Dammann, C. Li, J. H. Yoon, P. L. Chin, S. Bates, and G. P. Pfeifer, “Epigenetic inactivation of a RAS association domain family protein from the lung tumour suppressor locus 3p21.3,” Nature Genetics, vol. 25, no. 3, pp. 315–319, 2000.
[4]
L. van der Weyden and D. J. Adams, “The Ras-association domain family (RASSF) members and their role in human tumourigenesis,” Biochimica et Biophysica Acta, vol. 1776, no. 1, pp. 58–85, 2007.
[5]
A. Agathanggelou, S. Honorio, D. P. Macartney et al., “Methylation associated inactivation of RASSF1A from region 3p21.3 in lung, breast and ovarian tumours,” Oncogene, vol. 20, no. 12, pp. 1509–1518, 2001.
[6]
K. Dreijerink, E. Braga, I. Kuzmin et al., “The candidate tumor suppressor gene, RASSF1A, from human chromosome 3p21.3 is involved in kidney tumorigenesis,” Proceedings of the National Academy of Sciences of the United States of America, vol. 98, no. 13, pp. 7504–7509, 2001.
[7]
R. Dammann, T. Takahashi, and G. P. Pfeifer, “The CpG island of the novel tumor suppressor gene RASSF1A is intensely methylated in primary small cell lung carcinomas,” Oncogene, vol. 20, no. 27, pp. 3563–3567, 2001.
[8]
Y. G. Amaar, M. G. Minera, L. K. Hatran, D. D. Strong, S. Mohan, and M. E. Reeves, “Ras association domain family 1C protein stimulates human lung cancer cell proliferation,” American Journal of Physiology, vol. 291, no. 6, pp. L1185–L1190, 2006.
[9]
E. Estrabaud, I. Lassot, G. Blot et al., “RASSF1C, an isoform of the tumor suppressor RASSF1A, promotes the accumulation of β-catenin by interacting with βTrCP,” Cancer Research, vol. 67, no. 3, pp. 1054–1061, 2007.
[10]
M. D. Vos, C. A. Ellis, A. Bell, M. J. Birrer, and G. J. Clark, “Ras uses the novel tumor suppressor RASSF1 as an effector to mediate apoptosis,” Journal of Biological Chemistry, vol. 275, no. 46, pp. 35669–35672, 2000.
[11]
P. Rodriguez-Viciana, C. Sabatier, and F. McCormick, “Signaling specificity by ras family GTPases is determined by the full spectrum of effectors they regulate,” Molecular and Cellular Biology, vol. 24, no. 11, pp. 4943–4954, 2004.
[12]
H. Donninger, M. D. Vos, and G. J. Clark, “The RASSF1A tumor suppressor,” Journal of Cell Science, vol. 120, pp. 3163–3172, 2007.
[13]
S. Ortiz-Vega, A. Khokhlatchev, M. Nedwidek et al., “The putative tumor suppressor RASSF1A homodimerizes and heterodimerizes with the Ras-GTP binding protein Nore1,” Oncogene, vol. 21, no. 9, pp. 1381–1390, 2002.
[14]
L. Liu, S. Tommasi, D. H. Lee, R. Dammann, and G. P. Pfeifer, “Control of microtubule stability by the RASSF1A tumor suppressor,” Oncogene, vol. 22, no. 50, pp. 8125–8136, 2003.
[15]
A. Dallol, A. Agathanggelou, S. L. Fenton et al., “RASSF1A interacts with microtubule-associated proteins and modulates microtubule dynamics,” Cancer Research, vol. 64, no. 12, pp. 4112–4116, 2004.
[16]
L. Liu, A. Vo, and W. L. McKeehan, “Specificity of the methylation-suppressed A isoform of candidate tumor suppressor RASSF1 for microtubule hyperstabilization is determined by cell death inducer C19ORF5,” Cancer Research, vol. 65, no. 5, pp. 1830–1838, 2005.
[17]
L. Shivakumar, J. Minna, T. Sakamaki, R. Pestell, and M. A. White, “The RASSF1A tumor suppressor blocks cell cycle progression and inhibits cyclin D1 accumulation,” Molecular and Cellular Biology, vol. 22, no. 12, pp. 4309–4318, 2002.
[18]
A. Agathanggelou, I. Bieche, J. Ahmed-Choudhury et al., “Identification of novel gene expression targets for the ras association domain family 1 (RASSF1A) tumor suppressor gene in non-small cell lung cancer and neuroblastoma,” Cancer Research, vol. 63, no. 17, pp. 5344–5351, 2003.
[19]
S. Baksh, S. Tommasi, S. Fenton et al., “The tumor suppressor RASSF1A and MAP-1 link death receptor signaling to bax conformational change and cell death,” Molecular Cell, vol. 18, no. 6, pp. 637–650, 2005.
[20]
S. Rabizadeh, R. J. Xavier, K. Ishiguro et al., “The scaffold protein CNK1 interacts with the tumor suppressor RASSF1A and augments RASSF1A-induced cell death,” Journal of Biological Chemistry, vol. 279, no. 28, pp. 29247–29254, 2004.
[21]
D. Pan, “The hippo signaling pathway in development and cancer,” Developmental Cell, vol. 19, no. 4, pp. 491–505, 2010.
[22]
B. Zhao, K. Tumaneng, and K. L. Guan, “The Hippo pathway in organ size control, tissue regeneration and stem cell self-renewal,” Nature Cell Biology, vol. 13, no. 8, pp. 877–883, 2011.
[23]
A. Khokhlatchev, S. Rabizadeh, R. Xavier et al., “Identification of a novel Ras-regulated proapoptotic pathway,” Current Biology, vol. 12, no. 4, pp. 253–265, 2002.
[24]
H. Scheel and K. Hofmann, “A novel interaction motif, SARAH, connects three classes of tumor suppressor,” Current Biology, vol. 13, no. 23, pp. R899–R900, 2003.
[25]
M. Praskova, A. Khoklatchev, S. Ortiz-Vega, and J. Avruch, “Regulation of the MST1 kinase by autophosphorylation, by the growth inhibitory proteins, RASSF1 and NORE1, and by Ras,” Biochemical Journal, vol. 381, pp. 453–462, 2004.
[26]
E. Hwang, K. S. Ryu, K. Paakkonen et al., “Structural insight into dimeric interaction of the SARAH domains from Mst1 and RASSF family proteins in the apoptosis pathway,” Proceedings of the National Academy of Sciences of the United States of America, vol. 104, no. 22, pp. 9236–9241, 2007.
[27]
C. Guo, S. Tommasi, L. Liu, J. K. Yee, R. Dammann, and G. P. Pfeifer, “RASSF1A is part of a complex similar to the drosophila hippo/salvador/lats tumor-suppressor network,” Current Biology, vol. 17, no. 8, pp. 700–705, 2007.
[28]
C. Polesello, S. Huelsmann, N. H. Brown, and N. Tapon, “The Drosophila RASSF homolog antagonizes the hippo pathway,” Current Biology, vol. 16, no. 24, pp. 2459–2465, 2006.
[29]
H. J. Oh, K. K. Lee, S. J. Song et al., “Role of the tumor suppressor RASSF1A in Mst1-mediated apoptosis,” Cancer Research, vol. 66, no. 5, pp. 2562–2569, 2006.
[30]
C. Guo, X. Zhang, and G. P. Pfeifer, “The tumor suppressor RASSF1A prevents dephosphorylation of the mammalian STE20-like kinases MST1 and MST2,” Journal of Biological Chemistry, vol. 286, no. 8, pp. 6253–6261, 2011.
[31]
D. Matallanas, D. Romano, K. Yee et al., “RASSF1A elicits apoptosis through an MST2 pathway directing proapoptotic transcription by the p73 tumor suppressor protein,” Molecular Cell, vol. 27, no. 6, pp. 962–975, 2007.
[32]
J. Cai, N. Zhang, Y. Zheng, R. F. de Wilde, A. Maitra, and D. Pan, “The hippo signaling pathway restricts the oncogenic potential of an intestinal regeneration program,” Genes and Development, vol. 24, no. 21, pp. 2383–2388, 2010.
[33]
D. Zhou, Y. Zhang, H. Wu, et al., “Mst1 and Mst2 protein kinases restrain intestinal stem cell proliferation and colonic tumorigenesis by inhibition of Yes-associated protein (Yap) overabundance,” Proceedings of the National Academy of Sciences of the United States of America, vol. 108, no. 49, pp. E1312–E1320, 2011.
[34]
F. Ren, B. Wang, T. Yue, E. Y. Yun, Y. T. Ip, and J. Jiang, “Hippo signaling regulates Drosophila intestine stem cell proliferation through multiple pathways,” Proceedings of the National Academy of Sciences of the United States of America, vol. 107, no. 49, pp. 21064–21069, 2010.
[35]
L. van der Weyden, K. K. Tachibana, M. A. Gonzalez et al., “The RASSF1A isoform of RASSF1 promotes microtubule stability and suppresses tumorigenesis,” Molecular and Cellular Biology, vol. 25, no. 18, pp. 8356–8367, 2005.
[36]
S. Tommasi, R. Dammann, Z. Zhang et al., “Tumor susceptibility of Rassf1a knockout mice,” Cancer Research, vol. 65, no. 1, pp. 92–98, 2005.
[37]
D. Oceandy, A. Pickard, S. Prehar et al., “Tumor suppressor ras-association domain family 1 Isoform A is a novel regulator of cardiac hypertrophy,” Circulation, vol. 120, no. 7, pp. 607–616, 2009.
[38]
D. P. Del Re, T. Matsuda, P. Zhai et al., “Proapoptotic Rassf1A/Mst1 signaling in cardiac fibroblasts is protective against pressure overload in mice,” Journal of Clinical Investigation, vol. 120, no. 10, pp. 3555–3567, 2010.
[39]
A. L. Armesilla, J. C. Williams, M. H. Buch et al., “Novel functional interaction between the plasma membrane Ca2+ pump 4b and the proapoptotic tumor suppressor Ras-associated factor 1 (RASSF1),” Journal of Biological Chemistry, vol. 279, no. 30, pp. 31318–31328, 2004.
[40]
R. Agah, P. A. Frenkel, B. A. French, L. H. Michael, P. A. Overbeek, and M. D. Schneider, “Gene recombination in postmitotic cells: targeted expression of Cre recombinase provokes cardiac-restricted, site-specific rearrangement in adult ventricular muscle in vivo,” Journal of Clinical Investigation, vol. 100, no. 1, pp. 169–179, 1997.
[41]
H. Donninger, N. Allen, A. Henson et al., “Salvador protein is a tumor suppressor effector of RASSF1A with hippo pathway-independent functions,” Journal of Biological Chemistry, vol. 286, no. 21, pp. 18483–18491, 2011.
[42]
J. Heineke and J. D. Molkentin, “Regulation of cardiac hypertrophy by intracellular signalling pathways,” Nature Reviews Molecular Cell Biology, vol. 7, no. 8, pp. 589–600, 2006.
[43]
S. Yamamoto, G. Yang, D. Zablocki et al., “Activation of Mst1 causes dilated cardiomyopathy by stimulating apoptosis without compensatory ventricular myocyte hypertrophy,” Journal of Clinical Investigation, vol. 111, no. 10, pp. 1463–1474, 2003.
[44]
Y. Hao, A. Chun, K. Cheung, B. Rashidi, and X. Yang, “Tumor suppressor LATS1 is a negative regulator of oncogene YAP,” Journal of Biological Chemistry, vol. 283, no. 9, pp. 5496–5509, 2008.
[45]
Y. Matsui, N. Nakano, D. Shao et al., “Lats2 is a negative regulator of myocyte size in the heart,” Circulation Research, vol. 103, no. 11, pp. 1309–1318, 2008.
[46]
T. Heallen, M. Zhang, J. Wang et al., “Hippo pathway inhibits wnt signaling to restrain cardiomyocyte proliferation and heart size,” Science, vol. 332, no. 6028, pp. 458–461, 2011.
[47]
M. Xin, Y. Kim, L. B. Sutherland, et al., “Regulation of insulin-like growth factor signaling by Yap governs cardiomyocyte proliferation and embryonic heart size,” Science Signaling, vol. 4, no. 196, p. ra70, 2011.
[48]
D. Matallanas, D. Romano, F. Al-Mulla, et al., “Mutant K-Ras activation of the proapoptotic MST2 pathway is antagonized by wild-type K-Ras,” Molecular Cell, vol. 44, no. 6, pp. 893–906, 2011.
