Ubiquitous presence of gluconeogenic regulatory enzyme, fructose-1,6-bisphosphatase, within layers of rat retina

To shed some light on gluconeogenesis in mammalian retina, we have focused on fructose-1,6-bisphosphatase (FBPase), a regulatory enzyme of the process. The abundance of the enzyme within the layers of the rat retina suggests that, in mammals in contrast to amphibia, gluconeogenesis is not restricted to one specific cell of the retina. We propose that FBPase, in addition to its gluconeogenic role, participates in the protection of the retina against reactive oxygen species. Additionally, the nuclear localization of FBPase and of its binding partner, aldolase, in the retinal cells expressing the proliferation marker Ki-67 indicates that these two gluconeogenic enzymes are involved in non-enzymatic nuclear processes

Aldolase A is present in smooth muscle cell nuclei

Previously we have shown that aldolase (ALD; EC 4.1.2.13) is present in cardiomyocyte nuclei. Now, we focused our attention on ALD localization in smooth muscle cells. Immunocytochemical methods were used to study the subcellular localization of ALD. Aldolase was localized in the cytoplasm as well as in the nuclei. Within the nuclei ALD was located in the heterochromatin region. Native polyacrylamide gel electrophoresis followed by aldolase activity staining in gel was used to study the ALD isoenzyme pattern in porcine smooth muscle cells. Two ALD isoenzymes, A and C, were found in these cells but in the nuclei only the muscle isoenzyme was detected. To support the nuclear localization of ALD, measurement of aldolase activity in the smooth muscle cell nuclei isolated from porcine stomach was performed. The ALD activity in the isolated nuclei was detectable only after preincubation of the nuclear fraction with Triton X-100 and high concentration of KCl

Insulin/IGF1-PI3K-dependent nucleolar localization of a glycolytic enzyme -- phosphoglycerate mutase 2, is necessary for proper structure of nucleolus and RNA synthesis

Phosphoglycerate mutase (PGAM), a conserved, glycolytic enzyme has beenfound in nucleoli of cancer cells. Here, we present evidence that accumulation ofPGAM in the nucleolus is a universal phenomenon concerning not only neoplasticallytransformed but also non-malignant cells. Nucleolar localization of the enzyme isdependent on the presence of the PGAM2 (muscle) subunit and is regulated by insulin/IGF-1--PI3K signaling pathway as well as drugs influencing ribosomal biogenesis. Wedocument that PGAM interacts with several 40S and 60S ribosomal proteins and thatsilencing of PGAM2 expression results in disturbance of nucleolar structure, inhibitionof RNA synthesis and decrease of the mitotic index of squamous cell carcinoma cells.We conclude that presence of PGAM in the nucleolus is a prerequisite for synthesisand initial assembly of new pre-ribosome subunits

Insulin/IGF1-PI3K-dependent nucleolar localization of a glycolytic enzyme – phosphoglycerate mutase 2, is necessary for proper structure of nucleolus and RNA synthesis

Phosphoglycerate mutase (PGAM), a conserved, glycolytic enzyme has been\r\nfound in nucleoli of cancer cells. Here, we present evidence that accumulation of\r\nPGAM in the nucleolus is a universal phenomenon concerning not only neoplastically\r\ntransformed but also non-malignant cells. Nucleolar localization of the enzyme is\r\ndependent on the presence of the PGAM2 (muscle) subunit and is regulated by insulin/\r\nIGF-1–PI3K signaling pathway as well as drugs influencing ribosomal biogenesis. We\r\ndocument that PGAM interacts with several 40S and 60S ribosomal proteins and that\r\nsilencing of PGAM2 expression results in disturbance of nucleolar structure, inhibition\r\nof RNA synthesis and decrease of the mitotic index of squamous cell carcinoma cells.\r\nWe conclude that presence of PGAM in the nucleolus is a prerequisite for synthesis\r\nand initial assembly of new pre-ribosome subunits

Insulin/IGF1-PI3K-dependent nucleolar localization of a glycolytic enzyme : phosphoglycerate mutase 2, is necessary for proper structure of nucleolus and RNA synthesis

Phosphoglycerate mutase (PGAM), a conserved, glycolytic enzyme has been found in nucleoli of cancer cells. Here, we present evidence that accumulation of PGAM in the nucleolus is a universal phenomenon concerning not only neoplastically transformed but also non-malignant cells. Nucleolar localization of the enzyme is dependent on the presence of the PGAM2 (muscle) subunit and is regulated by insulin/IGF-1–PI3K signaling pathway as well as drugs influencing ribosomal biogenesis. We document that PGAM interacts with several 40S and 60S ribosomal proteins and that silencing of PGAM2 expression results in disturbance of nucleolar structure, inhibition of RNA synthesis and decrease of the mitotic index of squamous cell carcinoma cells. We conclude that presence of PGAM in the nucleolus is a prerequisite for synthesis and initial assembly of new pre-ribosome subunits