Low molecular weight phosphotyrosine protein phosphatase is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in humans is encoded by the ''ACP1''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
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.
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.
Also in other cancers, e.g.
colon cancer
Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel ...
, high ACP1 protein levels are linked to aggressive disease.
It has been suggested that ACP1 acts as a bona fide
oncogene
An oncogene is a gene that has the potential to cause cancer. In tumor cells, these genes are often mutated, or expressed at high levels. , but for now this notion remains unproven even if ACP1 overexpression drives cells towards a
Warburg effect-like glycolytic phenotype.
Apart from cancer, ACP1 has also been linked to osteoporosis as the enzyme plays an important role in the interaction of the
osteocyte
An osteocyte, an oblate-shaped type of bone cell with dendritic processes, is the most commonly found cell in mature bone. It can live as long as the organism itself. The adult human body has about 42 billion of them. Osteocytes do not divide an ...
with the bone environment,
while its inhibition appears useful for counteracting experimental
enous thromboembolism Currently, there are no clinically approved inhibitors that allow targeting ACP1 in patients.
Interactions
ACP1 has been shown to
interact with
EPH receptor A2 and
EPH receptor B1.
The proto-oncogene
Src has been suggested to be a direct target for ACP1 tyrosine phosphatase activity, but this has not been formally proven.
References
External links
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{{Protein tyrosine phosphatases
Human proteins