title: Low molecular weight protein tyrosine phosphatase: Multifaceted functions of an evolutionarily conserved enzyme.
abstract: Originally identified as a low molecular weight acid phosphatase, LMW-PTP is actually a protein tyrosine phosphatase that acts on many phosphotyrosine-containing cellular proteins that are primarily involved in signal transduction. Differences in sequence, structure, and substrate recognition as well as in subcellular localization in different organisms enable LMW-PTP to exert many different functions. In fact, during evolution, the LMW-PTP structure adapted to perform different catalytic actions depending on the organism type. In bacteria, this enzyme is involved in the biosynthesis of group 1 and 4 capsules, but it is also a virulence factor in pathogenic strains. In yeast, LMW-PTPs dephosphorylate immunophilin Fpr3, a peptidyl-prolyl-cis-trans isomerase member of the protein chaperone family. In humans, LMW-PTP is encoded by the ACP1 gene, which is composed of three different alleles, each encoding two active enzymes produced by alternative RNA splicing. In animals, LMW-PTP dephosphorylates a number of growth factor receptors and modulates their signalling processes. The involvement of LMW-PTP in cancer progression and in insulin receptor regulation as well as its actions as a virulence factor in a number of pathogenic bacterial strains may promote the search for potent, selective and bioavailable LMW-PTP inhibitors.
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy. Electronic address: anna.caselli@unifi.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Caselli
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy. Electronic address: paolo.paoli@unifi.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Paoli
authors.affiliation: Vascular Proteomics, Cancer Research UK Beatson Institute, Switchback Road, Glasgow G61 1BD, UK. Electronic address: a.santi@beatson.gla.ac.uk.
authors.forename: Alice
authors.initials: A
authors.lastname: Santi
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy. Electronic address: camilla.mugnaioni@unisi.it.
authors.forename: Camilla
authors.initials: C
authors.lastname: Mugnaioni
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy. Electronic address: alessandra.toti@student.unisi.it.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Toti
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy. Electronic address: guido.camici@unifi.it.
authors.forename: Guido
authors.initials: G
authors.lastname: Camici
authors.affiliation: Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Firenze, Viale Morgagni 50, 50134 Florence, Italy. Electronic address: paolo.cirri@unifi.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cirri
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D006801:Humans; D008970:Molecular Weight; D019000:Phosphotyrosine / Q000235:genetics / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction / Q000235:genetics
chemical_list: D019000:Phosphotyrosine; D017027:Protein Tyrosine Phosphatases
keywords: Bacterial PTPs; HCPTP; LMW-PTP; LMW-PTP IF1; LMW-PTP IF2; Phosphotyrosine phosphatases