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Leucine rich repeat containing 23
Symbols LRRC23 ; LRPB7
External IDs MGI1315192 HomoloGene5082 GeneCards: LRRC23 Gene
RNA expression pattern
PBB GE LRRC23 206076 at tn.png
More reference expression data
Species Human Mouse
Entrez 10233 16977
Ensembl ENSG00000010626 ENSMUSG00000030125
UniProt Q53EV4 O35125
RefSeq (mRNA) NM_001135217 NM_001302555
RefSeq (protein) NP_001128689 NP_001289484
Location (UCSC) Chr 12:
6.87 – 6.91 Mb
Chr 6:
124.77 – 124.78 Mb
PubMed search [2] [3]

Leucine-rich repeat-containing protein 23 is a protein that in humans is encoded by the LRRC23 gene.[1][2][3]


The function of LRRC23 is unknown. It is a member of the leucine-rich repeat family of proteins, which are known for participating in protein-protein interactions. Experimental evidence suggests that LRRC23 interacts with the CD28 protein in a pathway related to immune system and development of regulatory T cells that control spontaneous autoimmune disease.[4]

Protein Sequence[edit]

LRRC23 spans 343 residues containing two varieties of internally repeating sequence. Detected and aligned by RADAR,[5] the most abundant repeat is the leucine-rich repeat, repeating 9 times in bases 89-287. The other repeated sequence occurs twice in bases 3-36. The RADAR program output, below, summarizes the composition and location of all the repeats and aligns them for comparison against each other. LRRC23 RADAR Internal Repeats.png

The human genome produces three known variants of LRRC23.[3] The largest splice variant, variant 3, contains 8 exons. Variants 1 and 2 use alternative first exons, and variant 2 excludes the seventh exon, giving it a total of seven exons making up the mRNA.

Protein Structure[edit]

Although the actual structure of LRRC23 is unknown, comparison to the crystal structures of various similar proteins such as 2OMW_A (e-value 1.00e-17) reveals a structure typical of other leucine-rich repeat proteins. Alternating beta sheets and coils create a spiraled peptide chain forming an arch shape with beta-sheets occupying the concave surface [6].

The aligned structure of 2OMW_A with LRRC23 spans acids 72-272 of the LRRC23 protein. Conserved asparagines are highlighted in yellow, showing the regularity of spacing and repeat structure within. This model was generated using Cn3D software provided by NCBI.

CBlast 72-272 asparagines.png

Homology and Conservation[edit]

Predicted Post-Translational Modifications[edit]

Expression Statistics and Data[edit]


  1. ^ Tzachanis D, Berezovskaya A, Nadler LM, Boussiotis VA (2002). "Blockade of B7/CD28 in mixed lymphocyte reaction cultures results in the generation of alternatively activated macrophages, which suppress T-cell responses". Blood. 99 (4): 1465–73. PMID 11830501.  Unknown parameter |month= ignored (help)
  2. ^ Chang TT, Kuchroo VK, Sharpe AH (2002). "Role of the B7-CD28/CTLA-4 pathway in autoimmune disease". Curr Dir Autoimmun. 5: 113–30. PMID 11826754.  Unknown parameter |month= ignored (help)
  3. ^ a b "Entrez Gene: LRRC23 leucine rich repeat containing 23". 
  4. ^ Salomon B, Lenschow DJ, Rhee L, Ashourian N, Singh B, Sharpe A, Bluestone JA. 2000. B7/CD28 costimulation is essential for the homeostasis of the CD4+CD25+ immunoregulatory T cells that control autoimmune diabetes. Immunity 12(4):431-40.
  5. ^ RADAR: European Molecular Biology Laboratory - European Bioinformatics Institute (EMBLE-EBI) Radar program: [1]
  6. ^ NCBI Structure CBlast

Further reading[edit]

  • Maruyama K, Sugano S (1994). "Oligo-capping: a simple method to replace the cap structure of eukaryotic mRNAs with oligoribonucleotides". Gene. 138 (1-2): 171–4. doi:10.1016/0378-1119(94)90802-8. PMID 8125298. 
  • Ansari-Lari MA, Muzny DM, Lu J; et al. (1996). "A gene-rich cluster between the CD4 and triosephosphate isomerase genes at human chromosome 12p13". Genome Res. 6 (4): 314–26. doi:10.1101/gr.6.4.314. PMID 8723724. 
  • Bonaldo MF, Lennon G, Soares MB (1997). "Normalization and subtraction: two approaches to facilitate gene discovery". Genome Res. 6 (9): 791–806. doi:10.1101/gr.6.9.791. PMID 8889548. 
  • Ansari-Lari MA, Shen Y, Muzny DM; et al. (1997). "Large-scale sequencing in human chromosome 12p13: experimental and computational gene structure determination". Genome Res. 7 (3): 268–80. doi:10.1101/gr.7.3.268. PMID 9074930. 
  • Suzuki Y, Yoshitomo-Nakagawa K, Maruyama K; et al. (1997). "Construction and characterization of a full length-enriched and a 5'-end-enriched cDNA library". Gene. 200 (1-2): 149–56. doi:10.1016/S0378-1119(97)00411-3. PMID 9373149. 
  • Strausberg RL, Feingold EA, Grouse LH; et al. (2003). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMID 12477932. 
  • Gerhard DS, Wagner L, Feingold EA; et al. (2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)". Genome Res. 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMID 15489334. 
  • Tasheva ES, An K, Boyle DL, Conrad GW (2006). "Expression and localization of leucine-rich B7 protein in human ocular tissues". Mol. Vis. 11: 452–60. PMID 16030496. 

Category:LRR proteins [[File:Example.jpgExample.jpg]]