Pancreatic Stone Protein (PSP), also known as Lithostathine-1-alphaislet cells regeneration factor (ICRF) or islet of Langerhans regenerating protein (REG) is a protein that in humans is encoded by the REG1Agene as a single polypeptide of 144 amino acids further cleaved by trypsin to produce a 133 amino acid protein that is O-linked glycosylated on threonine 27. This protein is a type I subclass member of the Regenerating protein family. The Reg protein family is a multi protein family grouped into four subclasses, types I, II, III and IV based on the primary structures of the proteins.[4][5][6]
Reg family members REG1B, REGL, PAP and this gene are tandemly clustered on chromosome 2p12 and may have arisen from the same ancestral gene by gene duplication.[6]
The PSP is mostly produced in Human by the acinar cells of the pancreas and is secreted in the duodenum by the same pathway that pancreatic exocrine enzymes. It has C-terminal C-type lectin domain whose binding partner is currently unknown.
The blood PSP concentration has been shown to increase substantially in response to a sepsis event. Consequently, the use of the PSP as a biomarker of sepsis has been investigated thoroughly and the result of these researches confirmed the high diagnostic accuracy of the PSP for sepsis.[7] Of particular interest, PSP concentration has been shown to increase early in the development of a septic event, as illustrated in a cohort of severely burnt patients [8]
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De Caro AM, Adrich Z, Fournet B, Capon C, Bonicel JJ, De Caro JD, Rovery M (1989). "N-terminal sequence extension in the glycosylated forms of human pancreatic stone protein. The 5-oxoproline N-terminal chain is O-glycosylated on the 5th amino acid residue". Biochim. Biophys. Acta. 994 (3): 281–4. doi:10.1016/0167-4838(89)90305-1. PMID2493268.
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Otonkoski T, Mally MI, Hayek A (1994). "Opposite effects of beta-cell differentiation and growth on reg expression in human fetal pancreatic cells". Diabetes. 43 (9): 1164–6. doi:10.2337/diabetes.43.9.1164. PMID8070617.
Moriizumi S, Watanabe T, Unno M, Nakagawara K, Suzuki Y, Miyashita H, Yonekura H, Okamoto H (1994). "Isolation, structural determination and expression of a novel reg gene, human regI beta". Biochim. Biophys. Acta. 1217 (2): 199–202. doi:10.1016/0167-4781(94)90035-3. PMID8110835.
Bartoli C, Gharib B, Giorgi D, Sansonetti A, Dagorn JC, Bergé-Lefranc JL (1993). "A gene homologous to the reg gene is expressed in the human pancreas". FEBS Lett. 327 (3): 289–93. doi:10.1016/0014-5793(93)81006-L. PMID8348956. S2CID44565895.
