Identification of genes coding for serine/threonine phosphatases in Dictyostelium discoideum and functional characterization of type 4 protein phosphatase (PP4) / Identificação de genes codificadores de serina/treonina fosfatases em Dictyostelium discoideum e caracterização funcional da proteína fosfatase do tipo 4 (PP4)

AUTOR(ES)

Leonardo Costa Fiorini

DATA DE PUBLICAÇÃO

2003

RESUMO

The serine/threonine protein phosphatases (PPs) are enzymes responsible for dephosphorylation of phosphoserine and/or phosphothreonine residues and are divided in two gene families designated as PPP and PPM. The PPP family is divided in five subfamilies, which comprise type 1 (PP1), 2A (PP2A), 2B (PP2B), 5 (PP5) and 7 (PP7) phosphatases. This subdivision is based on aminoacid sequence similarity or enzyme domains. Novel PPs have been discovered in different organisms and classified in these families or subfamilies based on comparative sequence analysis. One of these is type 4 protein phosphatase (PP4), originally discovered in rabbit, which functions have been progressively uncovered. In this study our goal is to identify and characterize a novel serine/threonine phosphatase in Dictyostelium discoideum. We first screened a cDNA library and isolated a complete cDNA encoding the catalytic subunit of protein phosphatase 4 (PP4c), confirmed by manual DNA sequencing. The PP4c is an essential, single-copy gene located in chromosome 2, which encondes a mRNA constitutively expressed throughout D. discoideum life cycle. Immunodetection of PP4c performed with specific antibodies indicated corresponding protein levels. Overexpression of PP4c under a strong promoter caused no detectable phenotype. Subcellular localization of PP4c expressed as a GFP-fusion protein revealed its cytosolic location, in contrast to other organisms, where it has been reported to be enriched in centrosomes. We also describe here the genetic organization of PP4c, the genetic structure of all serine/threonine protein phosphatases belonging to the PPP family found in chromosome 2, and a phylogenetic analysis indicating relationships among these enzymes in D. discoideum and other selected organisms.

ASSUNTO(S)

enzimas phosphatase enzimes dictyostelium discoideum microbiology dna microbiologia fosfatase pp4 dna pp4 dictyostelium discoideum

Documentos Relacionados

• Targeting Protein Serine/Threonine Phosphatases for Drug Development
• Characterization of a Hank’s Type Serine/Threonine Kinase and Serine/Threonine Phosphoprotein Phosphatase in Pseudomonas aeruginosa
• Human cytomegalovirus carries serine/threonine protein phosphatases PP1 and a host-cell derived PP2A.
• PPX, a novel protein serine/threonine phosphatase localized to centrosomes.
• PPX, a novel protein serine/threonine phosphatase localized to centrosomes