Low molecular weight phosphotyrosine protein phosphatase is an enzyme that in humans is encoded by the ACP1gene.
The product of this gene belongs to the phosphotyrosine protein phosphatase family of proteins. It functions as an acid phosphatase and a protein tyrosine phosphatase by hydrolyzing protein tyrosine phosphate to protein tyrosine and orthophosphate. This enzyme also hydrolyzes orthophosphoric monoesters to alcohol and orthophosphate. This gene is genetically polymorphic, and three common alleles segregating at the corresponding locus give rise to six phenotypes. Each allele appears to encode at least two electrophoretically different isozymes, Bf and Bs, which are produced in allele-specific ratios. Three transcript variants encoding distinct isoforms have been identified for this gene.[5]
Clinical significance
Clinically, increased expression of ACP1 is a biomarker for poor prognosis in prostate cancer has been linked to worse clinical behaviour of prostate cancer, possibly outperforming the widely used Gleason grading system with respect to this important parameter.[6] Also in other cancers, e.g. colon cancer, high ACP1 protein levels are linked to aggressive disease.[7] It has been suggested that ACP1 acts as a bona fide oncogene, but for now this notion remains unproven even if ACP1 overexpression drives cells towards a Warburg effect-like glycolytic phenotype.[8] Apart from cancer, ACP1 has also been linked to osteoporosis as the enzyme plays an important role in the interaction of the osteocyte with the bone environment,[9] while its inhibition appears useful for counteracting experimental [venous thromboembolism].[10] Currently, there are no clinically approved inhibitors that allow targeting ACP1 in patients.
Interactions
ACP1 has been shown to interact with EPH receptor A2[11] and EPH receptor B1.[12] The proto-oncogene Src has been suggested to be a direct target for ACP1 tyrosine phosphatase activity, but this has not been formally proven.[13]
^Faria AV, Tornatore TF, Milani R, Queiroz KC, Sampaio IH, Fonseca EM, et al. (November 2017). "Oncophosphosignaling Favors a Glycolytic Phenotype in Human Drug Resistant Leukemia". Journal of Cellular Biochemistry. 118 (11): 3846–3854. doi:10.1002/jcb.26034. PMID28387439. S2CID3915599.
^Fernandes GV, Cavagis AD, Ferreira CV, Olej B, Leão M, Yano CL, et al. (June 2014). "Osteoblast adhesion dynamics: a possible role for ROS and LMW-PTP". Journal of Cellular Biochemistry. 115 (6): 1063–1069. doi:10.1002/jcb.24691. PMID24123071. S2CID7383008.
Overview of all the structural information available in the PDB for UniProt: P24666 (Human Low molecular weight phosphotyrosine protein phosphatase) at the PDBe-KB.
Overview of all the structural information available in the PDB for UniProt: Q9D358 (Mouse Low molecular weight phosphotyrosine protein phosphatase) at the PDBe-KB.
Further reading
Junien C, Kaplan JC, Bernheim A, Berger R (April 1979). "Regional assignment of red cell acid phosphatase locus to band 2p25". Human Genetics. 48 (1): 17–21. doi:10.1007/BF00273269. PMID457131. S2CID422040.
Dissing J, Johnsen AH (June 1992). "Human red cell acid phosphatase (ACP1): the primary structure of the two pairs of isozymes encoded by the ACP1*A and ACP1*C alleles". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1121 (3): 261–268. doi:10.1016/0167-4838(92)90155-7. PMID1627603.
Wakita Y, Narahara K, Takahashi Y, Kikkawa K, Kimura S, Oda M, Kimoto H (1986). "Duplication of 2p25: confirmation of the assignment of soluble acid phosphatase (ACP1) locus to 2p25". Human Genetics. 71 (3): 259–260. doi:10.1007/BF00284586. PMID4065897. S2CID10610694.
Blake NM, Kirk RL, Barnes KR, Thompson JM (June 1973). "Expression of human red cell acid phosphatase activity in placenta and other tissues". Jinrui Idengaku Zasshi. The Japanese Journal of Human Genetics. 18 (1): 10–23. PMID4356849.
Sensabaugh GF, Lazaruk KA (July 1993). "A TaqI site identifies the *A allele at the ACP1 locus". Human Molecular Genetics. 2 (7): 1079. doi:10.1093/hmg/2.7.1079-a. PMID8364553.
Bryson GL, Massa H, Trask BJ, Van Etten RL (November 1995). "Gene structure, sequence, and chromosomal localization of the human red cell-type low-molecular-weight acid phosphotyrosyl phosphatase gene, ACP1". Genomics. 30 (2): 133–140. doi:10.1006/geno.1995.9893. PMID8586411.
