Cingulin

Cingulin
Identifiers
Symbols CGN ; DKFZp779N1112; FLJ39281; KIAA1319
External IDs OMIM: 609473 MGI: 1927237 HomoloGene: 41394 GeneCards: CGN Gene
Orthologs
Species Human Mouse
Entrez 57530 70737
Ensembl ENSG00000143375 ENSMUSG00000068876
UniProt Q9P2M7 D3YUW7
RefSeq (mRNA) NM_020770 NM_001037711
RefSeq (protein) NP_065821 NP_001032800
Location (UCSC) Chr 1:
151.51 – 151.54 Mb		 Chr 3:
94.76 – 94.79 Mb
PubMed search

Cingulin (CGN; from the Latin cingere “to form a belt around”) is a cytosolic protein encoded by the CGN gene in humans[1][2][3] localized at tight junctions (TJs) of vertebrate epithelial and endothelial cells.

Discovery

Cingulin was originally discovered at the MRC Laboratory of Molecular Biology (Cambridge, UK) by Dr. Sandra Citi, as a protein present in chicken intestinal epithelial cells, that co-purified with non-muscle myosin II and was specifically localized at tight junctions (zonulae occludentes).[4]

Structure & interactions

Cingulin is a homodimer, each subunit containing a N-terminal globular "head" domain, a long α-helical coiled-coil "rod" domain and a small globular C-terminal "tail" region.[5] This organization is highly conserved throughout vertebrates.[1] However, cingulin homologs have not been detected in invertebrates.

In vitro, cingulin can bind to and bundle actin filaments, and interact with myosin II and several TJ proteins including ZO-1, ZO-2, ZO-3, paracingulin and occludin.[6][7][8] Moreover, cingulin forms a complex with JAM-A, a tight junction membrane protein.[6] Most of cingulin protein interactions are through the globular head domain. Cingulin interacts with ZO-1 through an N-terminal ZO-1 interacting motif (ZIM) in its head region.[9][10] The rod domain is involved in dimerization and interaction with the RhoA activator, GEF-H1.[11][12][13]

Cingulin has also been found to interact with microtubules (MTs) through the N-terminal head region, and these interactions was regulated by phosphorylation by the adenosine monophosphate-activated protein kinase (AMPK).[14]

Function

The function of cingulin has been studied by knockout (KO), knockdown (KD) and over-expression approaches. Embryoid bodies derived from embryonic stem cells where one or both cingulin alleles were targeted by homologous recombination show apparently normal tight junctions, but changes in the expression of a large number of genes, including tight junction protein genes (claudin-2, claudin-6, claudin-7 and occludin) and transcription factors (including GATA4).[9] Changes in the expression of claudin-2 and ZO-3 are also observed in cultured kidney cells (MDCK) depleted of cingulin by shRNA.[12]

In 2012, the phenotype of cingulin-knockout mice was described, proving that functional TJ in vivo can be formed in the absence of cingulin.[15] Together with paracingulin, cingulin also was reported to regulate claudin-2 expression through RhoA-dependent and independent mechanisms.[15][16] The role of cingulin in development has been studied by morpholino.[17] oligonucleotide-mediated depletion in chicken, indicating that cingulin is involved in neural crest development. In early mouse and frog embryos, maternal cingulin is localized in the cell cortex. Through early mouse development, cytocortical cingulin in present from oogenesis (cumulus-oocyte contact sites) until 16-cells morulae stage (apical microvillous zones) during early embryogenesis; then maternal cingulin is degraded by endocytic turn-over from the 32-cells stage. Regarding the zygotic cingulin, it accumulates at the tight junctions from 16-cells stage, 10 hours after ZO-1 assembly. Furthermore, the synthesis of cingulin in early mouse embryos is tissue-specific and it occurs in blastocyst (up-regulated in trophectoderm and down-regulated in inner-cells).[18][19] In Xenopus laevis embryos, maternal cingulin is recruited to apical cell-cell junctions from 2-cells stage.[20][21]

Homologs

In 2004, a protein homologous to cingulin was discovered and named JACOP (also known as paracingulin, or cingulin-like 1 protein; CGNL1).[13]

Human diseases

Although cingulin has been involved in regulation of RhoA signaling and gene expression in cultured cells and KO mice, nothing is known about the specific role of cingulin in human diseases.[11][12][15] Cingulin expression has been studied in human carcinomas and shown to be expressed in adenocarcinomas and down-regulated in squamous carcinomas.[22][23] Furthermore, histone deacetylase inhibitors, such as sodium butyrate, strongly upregulate its expression in some cultured cells.[24] Cingulin, as other junctional proteins could be used as a marker of epithelial differentiation, and as a diagnostic marker to distinguish adenocarcinomas from squamous carcinomas.

References

  1. 1 2 Citi S, D'Atri F, Parry DA (August 2000). "Human and Xenopus cingulin share a modular organization of the coiled-coil rod domain: predictions for intra- and intermolecular assembly". J. Struct. Biol. 131 (2): 135–45. doi:10.1006/jsbi.2000.4284. PMID 11042084.
  2. ↑ Nagase T, Kikuno R, Ishikawa KI, Hirosawa M, Ohara O (February 2000). "Prediction of the coding sequences of unidentified human genes. XVI. The complete sequences of 150 new cDNA clones from brain which code for large proteins in vitro". DNA Res. 7 (1): 65–73. doi:10.1093/dnares/7.1.65. PMID 10718198.
  3. ↑ "Entrez Gene: CGN cingulin".
  4. ↑ Citi S, Sabanay H, Jakes R, Geiger B, Kendrick-Jones J (May 1988). "Cingulin, a new peripheral component of tight junctions". Nature 333 (6170): 272–6. doi:10.1038/333272a0. PMID 3285223.
  5. ↑ Cordenonsi M, D'Atri F, Hammar E, Parry DA, Kendrick-Jones J, Shore D, Citi S (December 1999). "Cingulin contains globular and coiled-coil domains and interacts with ZO-1, ZO-2, ZO-3, and myosin". J. Cell Biol. 147 (7): 1569–82. doi:10.1083/jcb.147.7.1569. PMC 2174252. PMID 10613913.
  6. 1 2 Guillemot L, Citi S (2006). "Cingulin, a Cytoskeleton-Associated Protein of the Tight Junction". In Gonzalez-Mariscal L. Tight junctions. Georgetown, Texas: Landes Bioscience/Eurekah.com. pp. 54–63. ISBN 978-0-387-36673-9.
  7. ↑ D'Atri F, Citi S (2001). "Cingulin interacts with F-actin in vitro". FEBS Lett. 507 (1): 21–4. doi:10.1016/s0014-5793(01)02936-2. PMID 11682052.
  8. ↑ Cordenonsi M, Turco F, D'atri F, Hammar E, Martinucci G, Meggio F, Citi S (1999). "Xenopus laevis occludin. Identification of in vitro phosphorylation sites by protein kinase CK2 and association with cingulin". Eur. J. Biochem. 264 (2): 374–84. doi:10.1046/j.1432-1327.1999.00616.x. PMID 10491082.
  9. 1 2 Paschoud S, Yu D, Pulimeno P, Jond L, Turner JR, Citi S (2011). "Cingulin and paracingulin show similar dynamic behaviour, but are recruited independently to junctions". Mol. Membr. Biol. 28 (2): 123–35. doi:10.3109/09687688.2010.538937. PMID 21166484.
  10. ↑ Pulimeno P, Paschoud S, Citi S (2011). "A role for ZO-1 and PLEKHA7 in recruiting paracingulin to tight and adherens junctions of epithelial cells". J. Biol. Chem. 286 (19): 16743–50. doi:10.1074/jbc.M111.230862. PMC 3089516. PMID 21454477.
  11. 1 2 Citi S, Paschoud S, Pulimeno P, Timolati F, De Robertis F, Jond L, Guillemot L (2009). "The tight junction protein cingulin regulates gene expression and RhoA signaling". Ann. N. Y. Acad. Sci. 1165: 88–98. doi:10.1111/j.1749-6632.2009.04053.x. PMID 19538293.
  12. 1 2 3 Guillemot L, Citi S (2006). "Cingulin regulates claudin-2 expression and cell proliferation through the small GTPase RhoA". Mol. Biol. Cell 17 (8): 3569–77. doi:10.1091/mbc.E06-02-0122. PMC 1525245. PMID 16723500.
  13. 1 2 Aijaz S, D'Atri F, Citi S, Balda MS, Matter K (2005). "Binding of GEF-H1 to the tight junction-associated adaptor cingulin results in inhibition of Rho signaling and G1/S phase transition". Dev. Cell 8 (5): 777–86. doi:10.1016/j.devcel.2005.03.003. PMID 15866167.
  14. ↑ Yano T, Matsui T, Tamura A, Uji M, Tsukita S (2013). "The association of microtubules with tight junctions is promoted by cingulin phosphorylation by AMPK". J. Cell Biol. 203 (4): 605–14. doi:10.1083/jcb.201304194. PMC 3840929. PMID 24385485.
  15. 1 2 3 Guillemot L, Schneider Y, Brun P, Castagliuolo I, Pizzuti D, Martines D, Jond L, Bongiovanni M, Citi S (2012). "Cingulin is dispensable for epithelial barrier function and tight junction structure, and plays a role in the control of claudin-2 expression and response to duodenal mucosa injury". J. Cell. Sci. 125 (Pt 21): 5005–14. doi:10.1242/jcs.101261. PMID 22946046.
  16. ↑ Guillemot L, Spadaro D, Citi S (2013). "The junctional proteins cingulin and paracingulin modulate the expression of tight junction protein genes through GATA-4". PLoS ONE 8 (2): e55873. doi:10.1371/journal.pone.0055873. PMC 3567034. PMID 23409073.
  17. ↑ Kos R, Reedy MV, Johnson RL, Erickson CA (2001). "The winged-helix transcription factor FoxD3 is important for establishing the neural crest lineage and repressing melanogenesis in avian embryos". Development 128 (8): 1467–79. PMID 11262245.
  18. ↑ Javed Q, Fleming TP, Hay M, Citi S (1993). "Tight junction protein cingulin is expressed by maternal and embryonic genomes during early mouse development". Development 117 (3): 1145–51. PMID 8325239.
  19. ↑ Fleming TP, Hay M, Javed Q, Citi S (1993). "Localisation of tight junction protein cingulin is temporally and spatially regulated during early mouse development". Development 117 (3): 1135–44. PMID 8325238.
  20. ↑ Cardellini P, Davanzo G, Citi S (1996). "Tight junctions in early amphibian development: detection of junctional cingulin from the 2-cell stage and its localization at the boundary of distinct membrane domains in dividing blastomeres in low calcium". Dev. Dyn. 207 (1): 104–13. doi:10.1002/(SICI)1097-0177(199609)207:1<104::AID-AJA10>3.0.CO;2-0. PMID 8875080.
  21. ↑ Fesenko I, Kurth T, Sheth B, Fleming TP, Citi S, Hausen P (2000). "Tight junction biogenesis in the early Xenopus embryo". Mech. Dev. 96 (1): 51–65. doi:10.1016/s0925-4773(00)00368-3. PMID 10940624.
  22. ↑ Paschoud S, Bongiovanni M, Pache JC, Citi S (2007). "Claudin-1 and claudin-5 expression patterns differentiate lung squamous cell carcinomas from adenocarcinomas". Mod. Pathol. 20 (9): 947–54. doi:10.1038/modpathol.3800835. PMID 17585317.
  23. ↑ Citi S, Amorosi A, Franconi F, Giotti A, Zampi G (1991). "Cingulin, a specific protein component of tight junctions, is expressed in normal and neoplastic human epithelial tissues". Am. J. Pathol. 138 (4): 781–9. PMC 1886117. PMID 2012170.
  24. ↑ Bordin M, D'Atri F, Guillemot L, Citi S (2004). "Histone deacetylase inhibitors up-regulate the expression of tight junction proteins". Mol. Cancer Res. 2 (12): 692–701. PMID 15634758.

Further reading

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