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Куимов, А. Н.; Terekhov, S. M.

doi:10.1023/a:1023046031434

Cited by 6 publications

(1 citation statement)

References 14 publications

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“…3,4 A small fraction of Tank 1 is localized at telomeres, where it regulates the accessibility of telomeric DNA to telomerase. 5 Tank 1 is required for proper assembly of a bipolar spindle, but not for spindle poles themselves.…”

Section: Introductionmentioning

confidence: 99%

Intracellular distribution of Tankyrases as detected by multicolor immunofluorescence techniques

et al. 2012

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Poly(ADP-ribose) polymerases are a family of enzymes that catalyze the conversion of NAD+ into ADP-ribose. Among them, Tankyrases have been found to bind to centrosome, mitotic spindle and microsome proteins, in the cytoplasm, and to telomeres in the nucleus, where they play a relevant role in telomere metabolism. However, their precise intracellular localization during interphase has not been so far fully elucidated. We investigated this aspect in situ by double immunofluorescence experiments using antibodies recognizing Tankyrases 1–2 or other proteins residing in specific organelles (Golgi apparatus, mitochondria, lysosomes, endoplasmic reticulum). We used HeLa cells as a model system in vitro, before and after treatment with either actinomycin D or etoposide, to also investigate the possible relocation of Tankyrases during apoptosis. We observed that Tankyrases are distributed both in the nucleus and in the cytoplasm; in this latter compartment, they were found to colocate with the Golgi apparatus but never with the mitochondria; a pool of Tankyrases also colocates with the endoplasmic reticulum and lysosomes. Interestingly, in cells with clear signs of apoptosis, Tankyrases were detectable in the cytoplasmic blebs: this suggests that they are not massively cleaved during apoptosis and persist in the largely heterogeneous apoptotic remnants which are known to contain components of cytoplasmic and nuclear origin.

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Section: Introductionmentioning

confidence: 99%

Intracellular distribution of Tankyrases as detected by multicolor immunofluorescence techniques

et al. 2012

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Immunohistochemical detection of tankyrase 2 in human breast tumors and normal renal tissue

et al. 2005

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Tankyrase, which functions at telomeres and other cellular compartments, is thought to be a positive regulator of telomerase; its isoenzyme tankyrase 2 has been cloned as a putative cancer antigen. This pilot immunohistochemical study was designed to examine whether tumors overexpress tankyrase 2. An antibody was generated by using synthetic peptide specific for tankyrase 2 and was tested by Western blot and immunocytochemically; no cross-reaction with isoenzyme 1 was revealed. Among tissue sections, two tumors of 18 specimens were positive for tankyrase 2. Others were negative or contained barely detectable protein. The surrounding normal tissues were negative. Tankyrase 2 was also revealed in epithelial cells of a limited number of normal renal tubules, whereas other renal tissues were negative. These data suggest that tankyrase 2 is not expressed ubiquitously in human tissues. To determine whether the up-regulation of tankyrase 2 is associated with tissue regeneration and cell proliferation, we compared the activity and concentration of the enzyme in a model human embryonic kidney cell line 293 arrested by serum deprivation and restimulated with serum. The serum-starved quiescent cell culture exhibited detectable protein as did the proliferating cells; enzyme activity dramatically increased in the latter. We conclude that pathologic overexpression of tankyrase 2 in some tumors may be a result of the cancer-related adaptation of the malignant cells dependent on tankyrase activity. Under normal conditions, the protein might be up-regulated during cell differentiation and also posttranslationally in proliferating cells.

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Poly(ADP-ribosyl)ation of mannose-binding lectin out of human kidney cells

et al. 2011

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Mannose-binding lectin was identified as a substrate of tankyrase 2, an enzyme that catalyzes poly(ADP-ribosyl)ation. The endogenous tankyrase 2 was isolated out of cytoplasm of human embryonic kidney cells. It was bound to a soluble complex of at least two other proteins; they were identified using specific antibodies and other approaches as keratin 1 and mannose-binding lectin. Using immunoblot analysis and radioactive labeling, we detected tankyrase-2-dependent poly(ADP-ribosyl)ation of mannose-binding lectin. In the presence of NAD(+), the complex of keratin 1 and lectin was dissociated, what was recorded during elution of its separate components out of affinity columns and by decrease of their apparent molecular masses during gel-filtration. Tankyrase 2 also inhibited the carbohydrate-binding function of the lectin. The latter effect was observed using mannose-binding lectin out of human serum, which is free from keratin 1. As a result of tankyrase-2 activity, the lectin lost its affinity to mannan-agarose. The discovery of this new biochemical mechanism justifies further analysis of its physiological and medical significance.

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Cited by 6 publications

References 14 publications

Intracellular distribution of Tankyrases as detected by multicolor immunofluorescence techniques

Intracellular distribution of Tankyrases as detected by multicolor immunofluorescence techniques

Immunohistochemical detection of tankyrase 2 in human breast tumors and normal renal tissue

Poly(ADP-ribosyl)ation of mannose-binding lectin out of human kidney cells

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