User:JesseMorgan11/SMC4
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[edit ]Article Draft
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[edit ]Structural maintenance of chromosomes protein 4 (SMC-4) also known as chromosome-associated polypeptide C (CAP-C) or XCAP-C homolog is a protein that in humans is encoded by the SMC4 gene. SMC-4 is a core subunit of condensin I and II, large protein complexes involved in high order chromosome organization[1] , including condensation and segregation[2] . SMC-4 protein is commonly associated with the SMC-2 protein, another protein complex within the SMC protein family. SMC-4 dimerizes with SMC-2, creating the flexible and dynamic structure of the condensin holocomplex.[1] An over-expression of the SMC-4 protein is shown to impact carcinogenesis. [3] [4] [2]
Article body
[edit ]Structure and Interactions
[edit ]
The primary 5 domain structure of SMC proteins is highly conserved among species. The basic structure of SMC proteins are characterized by a non-helical hinge group, separated by two anti-parallel α-helical coiled-coil domains, along with two Amino-terminal globular domains containing ATP hydrolytic sites, or nucleotide-binding motifs located at the C-terminus and N-terminus called the Walker A and Walker B motifs.[5]
In eukaryotes, dimerization is mediated by the self-folding of the non-helical hinge group on the SMC protein. Dimerization occurs at the non-helical hinge group of SMC-4, which then associates with the non-helical hinge group of SMC-2, creating a "V" shaped heterodimeric structure. the holocomplex of condensin contains the SMC-4 and SMC-2 heterodimer subunits, along with 3 other non-SMC subunits, CAP-D2, CAP-G, and CAP-H.[2]
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In the condensin holocomplex, a protein subunit called kleisin joins the C-terminus and N-terminus ATPase end domains of both SMC-4 and SMC-2 proteins. when the condensin holocomplex is bound with ATP at these end domains, the condensin will assume a "closed" conformation state.[1] SMC-4 is a dynamic and flexible protein, allowing different domain components to occasionally interact with others. This is speculated to be involved in the mechanical ability of the complex when associated with chromosomes.[1] In budding yeast, these interactions my result in open "O" appearances, or collapsed "B" shaped states as a result of its dynamic ability.[6]
Clinical Significance of SMC-4
[edit ]The SMC-4 protein is associated with abnormal cell and tumor growth, and involved with migration and invasion. In general, the presence of over-expressed SMC-4 proteins is thought to be correlated with carcinogenesis.[3]
It is found that an over-expression or down-regulation of the SMC-4 protein alters TGFβ/Smad signaling pathways in glioma cells. SMC-4-transduced glioma cells showed activation of theTGFβ/Smad signaling pathway which was not present in SMC-4 silenced glioma cells. This pathway was shown to be correlated with an "aggressive" behavioral phenotype in glioma cells. An over-expression of SMC-4 can induce a higher rate of proliferation, and ultimately increased invasive capability. A down-regulation of SMC-4 reduced this quality. [3]
The SMC-4 protein is involved with normal lung development however, adenocarcinoma lung tissue shows an over-expression of SMC-4. additionally, SMC-4 may act as independent prognostic factor for carcinogenesis and lung adenocarcinoma. [2]
Studies suggest that over-expression of the SMC-4 protein in human liver tissue may be correlated with progression of hepatocellular carcinoma.[4]
References
[edit ]- ^ a b c d Eeftens, Jorine M.; Katan, Allard J.; Kschonsak, Marc; Hassler, Markus; de Wilde, Liza; Dief, Essam M.; Haering, Christian H.; Dekker, Cees (2016年03月01日). "Condensin Smc2-Smc4 Dimers Are Flexible and Dynamic". Cell Reports. 14 (8): 1813–1818. doi:10.1016/j.celrep.2016年01月06日3. ISSN 2211-1247. PMC 4785793 . PMID 26904946.
{{cite journal}}: no-break space character in|last5=at position 3 (help)CS1 maint: PMC format (link) - ^ a b c d Zhang, Chengli; Kuang, Manchao; Li, Meng; Feng, Lin; Zhang, Kaitai; Cheng, Shujun (2016年09月30日). "SMC4, which is essentially involved in lung development, is associated with lung adenocarcinoma progression". Scientific Reports. 6 (1): 34508. doi:10.1038/srep34508. ISSN 2045-2322. PMC 5043270 . PMID 27687868.
{{cite journal}}: CS1 maint: PMC format (link) - ^ a b c Jiang, L.; Zhou, J.; Zhong, D.; Zhou, Y.; Zhang, W.; Wu, W.; Zhao, Z.; Wang, W.; Xu, W.; He, L.; Ma, Y.; Hu, Y.; Zhang, W.; Li, J. (2017-03). "Overexpression of SMC4 activates TGFβ/Smad signaling and promotes aggressive phenotype in glioma cells". Oncogenesis. 6 (3): e301 – e301. doi:10.1038/oncsis.2017.8. ISSN 2157-9024. PMC 5533949 . PMID 28287612.
{{cite journal}}: Check date values in:|date=(help)CS1 maint: PMC format (link) - ^ a b Zhou, Bo; Chen, Hongxu; Wei, Dong; Kuang, Yi; Zhao, Xiaobiao; Li, Guangyao; Xie, Jun; Chen, Ping (2014年06月30日). "A novel miR-219-SMC4-JAK2/Stat3 regulatory pathway in human hepatocellular carcinoma". Journal of Experimental & Clinical Cancer Research. 33 (1): 55. doi:10.1186/1756-9966-33-55. ISSN 1756-9966. PMC 4096530 . PMID 24980149.
{{cite journal}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link) - ^ Hirano, Tatsuya (2002年02月15日). "The ABCs of SMC proteins: two-armed ATPases for chromosome condensation, cohesion, and repair". Genes & Development. 16 (4): 399–414. doi:10.1101/gad.955102. ISSN 0890-9369.
- ^ Ryu, Je-Kyung; Katan, Allard J.; van der Sluis, Eli O.; Wisse, Thomas; de Groot, Ralph; Haering, Christian H.; Dekker, Cees (2020). "The condensin holocomplex cycles dynamically between open and collapsed states". Nature Structural & Molecular Biology. 27 (12): 1134–1141. doi:10.1038/s41594-020-0508-3. ISSN 1545-9985.