CD93(Cluster ofDifferentiation 93) is aproteinthat in humans is encoded by theCD93gene.[5][6][7]CD93 is aC-type lectintransmembrane receptorwhich plays a role not only in cell–cell adhesion processes but also in host defense.[7]

CD93
Identifiers
AliasesCD93,C1QR1, C1qR(P), C1qRP, CDw93, ECSM3, MXRA4, dJ737E23.1, CD93 molecule
External IDsOMIM:120577;MGI:106664;HomoloGene:7823;GeneCards:CD93;OMA:CD93 - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_012072

NM_010740

RefSeq (protein)

NP_036204

NP_034870

Location (UCSC)Chr 20: 23.08 – 23.09 MbChr 2: 148.28 – 148.29 Mb
PubMedsearch[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Family

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CD93 belongs to the Group XIV C-Typelectinfamily,[8]a group containing three other members, endosialin (CD248), CLEC14A[9]andthrombomodulin,a well characterized anticoagulant. All of them contain a C-type lectin domain, a series ofepidermal growth factor like domains,a highly glycosylated mucin-like domain, a unique transmembrane domain and a short cytoplasmic tail. Due to their strong homology and their close proximity on chromosome 20, CD93 has been suggested to have arisen from the thrombomodulin gene through aduplicationevent.

Expression

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CD93 was originally identified in mice as an earlyB cellmarker through the use of AA4.1 monoclonal antibody.[10][11]Then this molecule was shown to be expressed on an early population ofhematopoietic stem cells,which give rise to the entire spectrum of mature cells in the blood. Now CD93 is known to be expressed by a wide variety of cells such asplatelets,monocytes,microgliaandendothelialcells. In the immune system CD93 is also expressed onneutrophils,activatedmacrophages,B cell precursors until the T2 stage in the spleen, a subset of dendritic cells and of natural killer cells. Molecular characterization of CD93 revealed that this protein is identical with C1qRp, a human protein identified as a putativeC1qreceptor.[12]C1q belongs to thecomplementactivation proteins and plays a major role in the activation of the classical pathway of the complement, which leads to the formation of the membrane attack complex. C1q is also involved in other immunological processes such as enhancement of bacterial phagocytosis, clearance ofapoptoticcells or neutralisation of virus. Strikingly, it has been shown that anti-C1qRp significantly reduced C1q enhanced phagocytosis. A more recent study confirmed that C1qRp is identical to CD93 protein, but failed to demonstrate a direct interaction between CD93 and C1q under physiological conditions. Recently it has been shown that CD93 is re-expressed during the late B cell differentiation and CD93 can be used in this context as a plasma cell maturation marker. CD93 has been found to be differentially expressed in grade IV glioma vasculature when compared to low grade glioma or normal brain and its high expression correlated with the poor survival of the patients.[13][14]

Function

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CD93 was initially thought to be a receptor for C1q, but now is thought to instead be involved in intercellularadhesionand in the clearance of apoptotic cells. The intracellular cytoplasmic tail of this protein contains two highly conserved domains which may be involved in CD93 function. Indeed, the highly charged juxtamembrane domain has been found to interact withmoesin,a protein known to play a role in linking transmembrane proteins to thecytoskeletonand in the remodelling of the cytoskeleton. This process appears crucial for both adhesion,migrationandphagocytosis,three functions in which CD93 may be involved.

In the context of late B cell differentiation, CD93 has been shown to be important for the maintenance of high antibody titres after immunization and in the survival oflong-lived plasma cellsin the bone marrow. Indeed, CD93 deficient mice failed to maintain high antibody level upon immunization and present a lower amount of antigen specific plasma cells in the bone marrow.

In the context of the endothelial cells, CD93 is involved in endothelial cell-cell adhesion, cell spreading, cell migration, cell polarization as well as tubular morphogenesis.[14]Recently it has been found that CD93 is able to control endothelial cell dynamics through its interaction with an extracellular matrix glycoprotein MMRN2.[15]Absence of CD93 or its interacting partner MMRN2 in the endothelial cells lead to disruption of extracellular matrix proteinfibronectinfibrillogenesis and decreasedintegrin B1activation.[15]

CD93 plays a significant role in the glioma development. CD93 knockout mice with glioma show smaller tumor size and improved survival.[14]The tumors also show disrupted fibronectin fibrillogenesis and decreasedintegrin B1activation.[15]

See also

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References

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  1. ^abcGRCh38: Ensembl release 89: ENSG00000125810Ensembl,May 2017
  2. ^abcGRCm38: Ensembl release 89: ENSMUSG00000027435Ensembl,May 2017
  3. ^"Human PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^"Mouse PubMed Reference:".National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^Nepomuceno RR, Henschen-Edman AH, Burgess WH, Tenner AJ (February 1997)."cDNA cloning and primary structure analysis of C1qR(P), the human C1q/MBL/SPA receptor that mediates enhanced phagocytosis in vitro".Immunity.6(2): 119–29.doi:10.1016/S1074-7613(00)80419-7.PMID9047234.
  6. ^Webster SD, Park M, Fonseca MI, Tenner AJ (January 2000). "Structural and functional evidence for microglial expression of C1qR(P), the C1q receptor that enhances phagocytosis".Journal of Leukocyte Biology.67(1): 109–16.doi:10.1002/jlb.67.1.109.PMID10648005.S2CID14982216.
  7. ^ab"Entrez Gene: CD93 CD93 molecule".
  8. ^Khan KA, McMurray J, Mohammed FM, Bicknell R (2019)."C-type lectin domain group 14 proteins in vascular biology, cancer and inflammation".FEBS Journal.286(17): 3299–3332.doi:10.1111/febs.14985.PMC6852297.PMID31287944.
  9. ^Mura M, Swain RK, Zhuang X, Vorschmitt H, Reynolds G, Durant S, Beesley JF, Herbert JM, Sheldon H, Andre M, Sanderson S, Glen K, Luu NT, McGettrick HM, Antczak P, Falciani F, Nash GB, Nagy ZS, Bicknell R (January 2012)."Identification and angiogenic role of the novel tumor endothelial marker CLEC14A".Oncogene.31(3): 293–305.doi:10.1038/onc.2011.233.PMID21706054.
  10. ^McKearn JP, Baum C, Davie JM (January 1984)."Cell surface antigens expressed by subsets of pre-B cells and B cells".Journal of Immunology.132(1): 332–9.doi:10.4049/jimmunol.132.1.332.PMID6606670.S2CID27256762.
  11. ^Zekavat G, Mozaffari R, Arias VJ, Rostami SY, Badkerhanian A, Tenner AJ, Nichols KE, Naji A, Noorchashm H (June 2010)."A novel CD93 polymorphism in non-obese diabetic (NOD) and NZB/W F1 mice is linked to a CD4+ iNKT cell deficient state".Immunogenetics.62(6): 397–407.doi:10.1007/s00251-010-0442-3.PMC2875467.PMID20387063.
  12. ^McGreal EP, Ikewaki N, Akatsu H, Morgan BP, Gasque P (May 2002)."Human C1qRp is identical with CD93 and the mNI-11 antigen but does not bind C1q".Journal of Immunology.168(10): 5222–32.doi:10.4049/jimmunol.168.10.5222.PMID11994479.
  13. ^Dieterich LC, Mellberg S, Langenkamp E, Zhang L, Zieba A, Salomäki H, Teichert M, Huang H, Edqvist PH, Kraus T, Augustin HG, Olofsson T, Larsson E, Söderberg O, Molema G, Pontén F, Georgii-Hemming P, Alafuzoff I, Dimberg A (November 2012). "Transcriptional profiling of human glioblastoma vessels indicates a key role of VEGF-A and TGFβ2 in vascular abnormalization".The Journal of Pathology.228(3): 378–90.doi:10.1002/path.4072.PMID22786655.S2CID31223309.
  14. ^abcLangenkamp E, Zhang L, Lugano R, Huang H, Elhassan TE, Georganaki M, Bazzar W, Lööf J, Trendelenburg G, Essand M, Pontén F, Smits A, Dimberg A (November 2015)."Elevated expression of the C-type lectin CD93 in the glioblastoma vasculature regulates cytoskeletal rearrangements that enhance vessel function and reduce host survival".Cancer Research.75(21): 4504–16.doi:10.1158/0008-5472.CAN-14-3636.PMID26363010.
  15. ^abcLugano R, Vemuri K, Yu D, Bergqvist M, Smits A, Essand M, Johansson S, Dejana E, Dimberg A (August 2018)."CD93 promotes β1 integrin activation and fibronectin fibrillogenesis during tumor angiogenesis".The Journal of Clinical Investigation.128(8): 3280–3297.doi:10.1172/JCI97459.PMC6063507.PMID29763414.

Further reading

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