αE-catenin, also known as Catenin alpha-1 is a protein that in humans is encoded by the CTNNA1gene.[5][6] αE-catenin is highly expressed in cardiac muscle and localizes to adherens junctions at intercalated disc structures where it functions to mediate the anchorage of actin filaments to the sarcolemma. αE-catenin also plays a role in tumor metastasis and skin cell function.
Though αE-catenin exhibits substantial expression in cardiac muscle, αE-catenin is most well known for role in metastasizing tumor cells.[11] αE-catenin also plays a role in epithelial tissue, both at adherens junctions and in signaling pathways.[12]
Functional αE-catenin is required for normal embryonic development, as a mutation eliminating the C-terminal 1/3 of the protein resulting in a complete loss-of-function phenotype showed disruption of the trophoblastepithelium and arrested development at the blastocyst stage.[14]
αE-catenin specifically, not β- or γ-catenin, binds F-actin and organizes and tethers the filaments at regions of cell-cell contact. Studies show that full-length αE-catenin binds and bundles F-actin in a superior fashion relative to individual N-terminal or C-terminal domains.[15]
αE-catenin, along with β-catenin and plakoglobin form distinct complexes with N-cadherin that are involved in forming cell-cell contacts and differentiation of cardiomyocytes. Catenin-N-cadherin complexes are apparently necessary for and precede the first cell to cell contact, precursory to gap junction formation.[16] The anchorage of cadherin-catenin complexes to actin filaments by αE-catenin is regulated by tyrosinephosphorylation.[17]
Functional insights into αE-catenin function have come from studies employing transgenesis. Mice harboring a cardiac-specific deletion of αE-catenin exhibited abnormalities in cardiac dimensions and function, representative of dilated cardiomyopathy. This was further characterized by disorganization of intercalated disc structures and mitochondria, as well as compensatory increases in β-catenin and decreases in localization of cadherin and vinculin at intercalated discs. Knockout mice also exhibited high susceptibility to death following stress.[18]
Clinical significance
This section is empty. You can help by adding to it. (July 2015)
^Janssens B, Goossens S, Staes K, Gilbert B, van Hengel J, Colpaert C, Bruyneel E, Mareel M, van Roy F (Sep 2001). "alphaT-catenin: a novel tissue-specific beta-catenin-binding protein mediating strong cell-cell adhesion". Journal of Cell Science. 114 (Pt 17): 3177–88. doi:10.1242/jcs.114.17.3177. PMID11590244.
^Breen E, Clarke A, Steele G, Mercurio AM (Dec 1993). "Poorly differentiated colon carcinoma cell lines deficient in alpha-catenin expression express high levels of surface E-cadherin but lack Ca(2+)-dependent cell-cell adhesion". Cell Adhesion and Communication. 1 (3): 239–50. doi:10.3109/15419069309097257. PMID8081881.
^Hertig CM, Butz S, Koch S, Eppenberger-Eberhardt M, Kemler R, Eppenberger HM (Jan 1996). "N-cadherin in adult rat cardiomyocytes in culture. II. Spatio-temporal appearance of proteins involved in cell-cell contact and communication. Formation of two distinct N-cadherin/catenin complexes". Journal of Cell Science. 109 (1): 11–20. doi:10.1242/jcs.109.1.11. PMID8834786.
^Oyama T, Kanai Y, Ochiai A, Akimoto S, Oda T, Yanagihara K, Nagafuchi A, Tsukita S, Shibamoto S, Ito F (December 1994). "A truncated beta-catenin disrupts the interaction between E-cadherin and alpha-catenin: a cause of loss of intercellular adhesiveness in human cancer cell lines". Cancer Res. 54 (23): 6282–7. PMID7954478.
^Navarro P, Lozano E, Cano A (August 1993). "Expression of E- or P-cadherin is not sufficient to modify the morphology and the tumorigenic behavior of murine spindle carcinoma cells. Possible involvement of plakoglobin". J. Cell Sci. 105 (4): 923–34. doi:10.1242/jcs.105.4.923. hdl:10261/78716. PMID8227214.
^Klingelhöfer J, Troyanovsky RB, Laur OY, Troyanovsky S (August 2000). "Amino-terminal domain of classic cadherins determines the specificity of the adhesive interactions". J. Cell Sci. 113 (16): 2829–36. doi:10.1242/jcs.113.16.2829. PMID10910767.
^Lewalle JM, Bajou K, Desreux J, Mareel M, Dejana E, Noël A, Foidart JM (December 1997). "Alteration of interendothelial adherens junctions following tumor cell-endothelial cell interaction in vitro". Exp. Cell Res. 237 (2): 347–56. doi:10.1006/excr.1997.3799. hdl:2268/61990. PMID9434630.
^Shasby DM, Ries DR, Shasby SS, Winter MC (June 2002). "Histamine stimulates phosphorylation of adherens junction proteins and alters their link to vimentin". Am. J. Physiol. Lung Cell Mol. Physiol. 282 (6): L1330–8. CiteSeerX10.1.1.1000.5266. doi:10.1152/ajplung.00329.2001. PMID12003790.
Further reading
Nagafuchi A, Takeichi M, Tsukita S (1991). "The 102 kd cadherin-associated protein: similarity to vinculin and posttranscriptional regulation of expression". Cell. 65 (5): 849–57. doi:10.1016/0092-8674(91)90392-C. PMID1904011. S2CID38622586.
Oyama T, Kanai Y, Ochiai A, Akimoto S, Oda T, Yanagihara K, Nagafuchi A, Tsukita S, Shibamoto S, Ito F (1994). "A truncated beta-catenin disrupts the interaction between E-cadherin and alpha-catenin: a cause of loss of intercellular adhesiveness in human cancer cell lines". Cancer Res. 54 (23): 6282–7. PMID7954478.
Oda T, Kanai Y, Shimoyama Y, Nagafuchi A, Tsukita S, Hirohashi S (1993). "Cloning of the human alpha-catenin cDNA and its aberrant mRNA in a human cancer cell line". Biochem. Biophys. Res. Commun. 193 (3): 897–904. doi:10.1006/bbrc.1993.1710. PMID8323564.
Furukawa Y, Nakatsuru S, Nagafuchi A, Tsukita S, Muto T, Nakamura Y, Horii A (1993). "Structure, expression and chromosome assignment of the human catenin (cadherin-associated protein) alpha 1 gene (CTNNA1)". Cytogenet. Cell Genet. 65 (1–2): 74–8. doi:10.1159/000133603. PMID8404069.