ABSTRACT
p21-Activated protein kinase 2 (PAK-2) has both anti- and pro-apoptotic functions depending on its mechanism of activation. Activation of full-length PAK-2 by the monomeric GTPases Cdc42 or Rac stimulates cell survival, whereas caspase activation of PAK-2 to the PAK-2p34 fragment is involved in the apoptotic response. In this study we use functional knockout of PAK-2 and gene replacement with the caspase cleavage-deficient PAK-2D212N mutant to differentiate the biological functions of full-length PAK-2 and caspase-activated PAK-2p34. Knockout of PAK-2 results in embryonic lethality at early stages before organ development, whereas replacement with the caspase cleavage-deficient PAK-2D212N results in viable and healthy mice, indicating that early embryonic lethality is caused by deficiency of full-length PAK-2 rather than lack of caspase activation to the PAK-2p34 fragment. However, deficiency of caspase activation of PAK-2 decreased spontaneous cell death of primary mouse embryonic fibroblasts and increased cell growth at high cell density. In contrast, stress-induced cell death by treatment with the anti-cancer drug cisplatin was not reduced by deficiency of caspase activation of PAK-2, but switched from an apoptotic to a nonapoptotic, caspase-independent mechanism. Homozygous PAK-2D212N primary mouse embryonic fibroblasts that lack the ability to generate the proapoptotic PAK-2p34 show less activation of the effector caspase 3, 6, and 7, indicating that caspase activation of PAK-2 amplifies the apoptotic response through a positive feedback loop resulting in more activation of effector caspases.
Subject(s)
Apoptosis/genetics , CARD Signaling Adaptor Proteins/genetics , Peptide Fragments/metabolism , p21-Activated Kinases/genetics , p21-Activated Kinases/metabolism , Animals , Blotting, Southern , Blotting, Western , CARD Signaling Adaptor Proteins/metabolism , Caspases, Effector/metabolism , Cisplatin , DNA Primers/genetics , Feedback, Physiological , Fibroblasts , Genetic Vectors , Mice , Mice, Knockout , Mutation, Missense/genetics , Peptide Fragments/genetics , Polymerase Chain ReactionABSTRACT
This study aims to explore the prevalence of clinic-based research among accredited marriage and family therapy (MFT) programs and reveal rationales explaining why academic settings may or may not be conducting clinical research. Findings of this project are the result of electronic-mail surveys completed by 26 accredited MFT programs. Approximately one-half of the respondents reported currently conducting clinic-based research. Open-ended responses reveal factors that lead to research success and failure, as well as reasons research was not being conducted at training programs.
