Leucine rich repeat containing 15 is a cell membrane-expressed protein. In humans it is encoded by the LRRC15 [5]gene.[6] It is located on chromosome 3 at 3q29. It belongs to the LRR superfamily, which is involved in cell–cell and cell–ECM interactions.
Preliminary evidence indicates that expression may be related to the severity of COVID-19[7] and that it is an inhibitory accessory factor for SARS-CoV-2 cell entry.[8][9][10][11]
LRRC15 lacks obvious intracellular domains. LRRC15 displays a highly restricted expression pattern, but is expressed in areas that make up innate immune barriers such as the placenta, skin, activated fibroblasts in wounds, and lymphoid tissues such as the spleen.[citation needed]
LRRC15 may play some role in innate immunity.
LRRC15 is aberrantly expressed in cancer. It is highly expressed in CAFs within the stroma of numerous solid tumors and directly expressed in mesenchymal tumors such as glioblastoma, sarcomas, and melanoma.[citation needed]
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Gisby JS, Buang NB, Papadaki A, Clarke CL, Malik TH, Medjeral-Thomas N, Pinheiro D, Mortimer PM, Lewis S, Sandhu E, McAdoo SP, Prendecki MF, Willicombe M, Pickering MC, Botto M, Thomas DC, Peters JE (2022). "Multi-omics identify LRRC15 as a COVID-19 severity predictor and persistent pro-1 thrombotic signals in convalescence". medRxiv10.1101/2022.04.29.22274267v1.
^Shilts J, Crozier TM, Teixeira-Silva A, Gabaev I, Greenwood ED, Watson SJ, Ortmann BM, Gawden-Bone CM, Pauzaite T, Hoffmann M, Nathan JA, Pöhlmann S, Lehner PJ, Wright GJ (2021). "LRRC15 mediates an accessory interaction with the SARS-CoV-2 spike protein". bioRxiv10.1101/2021.09.25.461776.
^Song J, Chow RD, Pena-Hernandez M, Zhang L, Loeb SA, So E, Liang OD, Wilen CB, Lee S. "LRRC15 is an inhibitory receptor blocking SARS-CoV-2 spike-mediated entry in trans". bioRxiv10.1101/2021.11.23.469714.
Satoh K, Hata M, Yokota H (January 2002). "A novel member of the leucine-rich repeat superfamily induced in rat astrocytes by beta-amyloid". Biochemical and Biophysical Research Communications. 290 (2): 756–62. doi:10.1006/bbrc.2001.6272. PMID11785964.
Satoh K, Hata M, Shimizu T, Yokota H, Akatsu H, Yamamoto T, Kosaka K, Yamada T (September 2005). "Lib, transcriptionally induced in senile plaque-associated astrocytes, promotes glial migration through extracellular matrix". Biochemical and Biophysical Research Communications. 335 (2): 631–6. doi:10.1016/j.bbrc.2005.07.117. PMID16098915.