Comparative study of trauma in the elderly and non-elderly patients in a University Hospital in Curitiba.

Objective: To compare and identify differences in the profile of elderly and non-elderly patients with trauma.

Methods: We conducted a comparative, cross-sectional, retrospective, quantitative study with 3112 patients between November, 25th 2010 and February, 25th 2011; patients were classified into GI: elderly (60 years or older) and GA: non-elderly (13-59 years). We collected information on the mechanism of trauma, injuries and factors associated with the event, which were compared between groups by using chi-square, Student t and proportions tests.

Mouse model for probing tumor suppressor activity of protein phosphatase 2A in diverse signaling pathways.

Evidence that protein phosphatase 2A (PP2A) is a tumor suppressor in humans came from the discovery of mutations in the genes encoding the Aα and Aβ subunits of the PP2A trimeric holoenzymes, Aα-B-C and Aβ-B-C. One point mutation, Aα-E64D, was found in a human lung carcinoma. It renders Aα specifically defective in binding regulatory B' subunits.

Human cancer-associated mutations in the Aα subunit of protein phosphatase 2A increase lung cancer incidence in Aα knock-in and knockout mice.

Strong evidence has indicated that protein phosphatase 2A (PP2A) is a tumor suppressor, but a mouse model for testing the tumor suppressor activity was missing. The most abundant forms of trimeric PP2A holoenzyme consist of the scaffolding Aα subunit, one of several regulatory B subunits, and the catalytic Cα subunit. Aα mutations were discovered in a variety of human carcinomas.

Purification of PP2A holoenzymes by sequential immunoprecipitation with anti-peptide antibodies.

Understanding the multiple functions of protein phosphatase 2A (PP2A) rests on elucidating the enzymatic properties of over 50 different possible forms of the PP2A holoenzyme. We describe a procedure for highly purifying each one of these forms. This procedure is based on coexpressing in 293 cells one scaffolding A subunit, one regulatory B subunit, and one catalytic C subunit, each tagged with a different sequence, and purifying the trimeric holoenzyme by three consecutive immunoprecipitations with antibodies against the tags.

Mutagenesis and expression of the scaffolding Aalpha and Abeta subunits of PP2A: assays for measuring defects in binding of cancer-related Aalpha and Abeta mutants to the regulatory B and catalytic C subunits.

Protein phosphatase 2A (PP2A) holoenzymes are composed of three subunits: one scaffolding A subunit, one regulatory B subunit, and one catalytic C subunit. The A subunit exists as two isoforms: Aalpha and Abeta. The C subunit also exists as two isoforms (Calpha and Cbeta) and B subunits fall into three families (B, B', and B") comprising over 15 members.

Characterization of the Aalpha and Abeta subunit isoforms of protein phosphatase 2A: differences in expression, subunit interaction, and evolution.

Protein phosphatase 2A (PP2A) is very versatile owing to a large number of regulatory subunits and its ability to interact with numerous other proteins. The regulatory A subunit exists as two closely related isoforms designated Aalpha and Abeta. Mutations have been found in both isoforms in a variety of human cancers.

Protein phosphatase 2A holoenzyme assembly: identification of contacts between B-family regulatory and scaffolding A subunits.

Protein serine/threonine phosphatase (PP) 2A is a ubiquitous enzyme with pleiotropic functions. Trimeric PP2A consists of a structural A subunit, a catalytic C subunit, and a variable regulatory subunit. Variable subunits (B, B', and B" families) dictate PP2A substrate specificity and subcellular localization.

Reduced expression of the Aalpha subunit of protein phosphatase 2A in human gliomas in the absence of mutations in the Aalpha and Abeta subunit genes.

Protein phosphatase 2A (PP2A) consists of 3 subunits: the catalytic subunit, C, and the regulatory subunits, A and B. The A and C subunits both exist as 2 isoforms (alpha and beta) and the B subunit as multiple forms subdivided into 3 families, B, B' and B". It has been reported that the genes encoding the Aalpha and Abeta subunits are mutated in various human cancers, suggesting that they may function as tumor suppressors.

Alterations in protein phosphatase 2A subunit interaction in human carcinomas of the lung and colon with mutations in the A beta subunit gene.

Protein phosphatase 2A (PP2A) consists of three subunits, A, B and C. The A and B subunits have regulatory functions while C is the catalytic subunit. PP2A core enzyme is composed of subunits A and C, and the holoenzyme of subunits A, B and C.

Disruption of protein phosphatase 2A subunit interaction in human cancers with mutations in the A alpha subunit gene.

The A subunit of protein phosphatase 2A (PP2A) consists of 15 nonidentical repeats. The catalytic C subunit binds to C-terminal repeats 11 - 15 and regulatory B subunits bind to N-terminal repeats 1 - 10. Recently, four cancer-associated mutants of the A-alpha subunit have been described: Glu64-->Asp in lung carcinoma, Glu64-->Gly in breast carcinoma, Arg418-->Trp in melanoma, and Delta171 - 589 in breast carcinoma.

Binding specificity of protein phosphatase 2A core enzyme for regulatory B subunits and T antigens.

The core enzyme of protein phosphatase 2A is composed of a regulatory subunit A and a catalytic subunit C. It is controlled by three types of regulatory B subunits (B, B', and B") and by tumor (T) antigens, which are unrelated by sequence but bind to overlapping regions on the A subunit. To find out whether the different B subunits and T antigens bind to identical or distinct amino acids of the A subunit, mutants were generated and their abilities to bind B subunits and T antigens were tested.

Increasing the ratio of PP2A core enzyme to holoenzyme inhibits Tat-stimulated HIV-1 transcription and virus production.

We demonstrated previously that PP2A exists in many cell types as two abundant forms: (1) holoenzyme composed of two regulatory subunits, A and B, and a catalytic subunit C; and (2) core enzyme consisting of the A and C subunits. These two forms have different substrate specificities. Since published data suggested that HIV-1 transcription may be regulated by a cellular protein phosphatase, it was of interest to determine whether changing the ratio between PP2A core and holoenzyme affects HIV-1 gene expression.

Molecular model of the A subunit of protein phosphatase 2A: interaction with other subunits and tumor antigens.

Protein phosphatase 2A consists of three subunits, the catalytic subunit (C) and two regulatory subunits (A and B). The A subunit has a rod-like shape and consists of 15 nonidentical repeats. It binds the catalytic subunit through repeats 11 to 15 at the C terminus and the tumor antigens encoded by small DNA tumor viruses through overlapping but distinct regions at N-terminal repeats 2 to 8.

Identification of binding sites on the regulatory A subunit of protein phosphatase 2A for the catalytic C subunit and for tumor antigens of simian virus 40 and polyomavirus.

Protein phosphatase 2A is composed of three subunits: the catalytic subunit C and two regulatory subunits, A and B. The A subunit consists of 15 nonidentical repeats and has a rodlike shape. It is associated with the B and C subunits as well as with the simian virus 40 small T, polyomavirus small T, and polyomavirus medium T tumor antigens.

Constant expression and activity of protein phosphatase 2A in synchronized cells.

The levels of the A, B, and C subunits of protein phosphatase 2A in extracts from synchronized embryonic bovine tracheal cells were determined by immunoblotting with subunit-specific antibodies. A constant amount of each subunit was found in resting cells as well as in growing cells from all stages of the cell cycle. The phosphatase activity of protein phosphatase 2A was also constant.

Association of protein phosphatase 2A with polyoma virus medium tumor antigen.

The polyoma virus medium and small tumor antigens, as well as simian virus 40 small tumor antigen, form specific complexes with two cellular proteins designated 61- and 37-kDa proteins. In this report, we demonstrate that the 61- and 37-kDa proteins correspond to the A and C subunits, respectively, of the serine- and threonine-specific protein phosphatase 2A (PP2A). On the one hand, antibodies raised against the 61-kDa protein reacted specifically with the purified A subunit of PP2A.