The Nucleolar Targeting Signal (NTS) of Parathyroid Hormone Related Protein Mediates Endocytosis and Nucleolar Translocation

Aarts, Michelle; Rix, Anna S.; Guo, Jun; Bringhurst, R.; Henderson, Janet E.

doi:10.1359/jbmr.1999.14.9.1493

Cited by 87 publications

(62 citation statements)

References 42 publications

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“…These features allow PTHrP either to be secreted in a paracrine/autocrine fashion or to be retained within the cytosol and to be translocated to the nucleus (4,6,7). Alternative potential mechanisms of PTHrP entry into the cytosol have also been described (8)(9)(10).…”

Section: Ntranuclear Transport Of Numerous Polypeptide Ligands Has mentioning

confidence: 99%

Severe growth retardation and early lethality in mice lacking the nuclear localization sequence and C-terminus of PTH-related protein

Miao

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

114

113

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Parathyroid hormone (PTH) plays a central role in the regulation of serum calcium and phosphorus homeostasis, while parathyroid hormone-related protein (PTHrP) has important developmental roles. Both peptides signal through the same G protein-coupled receptor, the PTH/PTHrP or PTH type 1 receptor (PTH1R). PTHrP, normally a secreted protein, also contains a nuclear localization signal (NLS) that in vitro imparts functionality to the protein at the level of the nucleus. We investigated this functionality in vivo by introducing a premature termination codon in Pthrp in ES cells and generating mice that express PTHrP (1-84), a truncated form of the protein that is missing the NLS and the C-terminal region of the protein but can still signal through its cell surface receptor. Mice homozygous for the knock-in mutation (Pthrp KI) displayed retarded growth, early senescence, and malnutrition leading postnatally to their rapid demise. Decreased cellular proliferative capacity and increased apoptosis in multiple tissues including bone and bone marrow cells were associated with altered expression and subcellular distribution of the senescenceassociated tumor suppressor proteins p16 INK4a and p21 and the oncogenes Cyclin D, pRb, and Bmi-1. These findings provide in vivo experimental proof that substantiates the biologic relevance of the NLS and C-terminal portion of PTHrP, a polypeptide ligand that signals mainly via a cell surface G protein-coupled receptor.ageing ͉ nucleus ͉ osteoporosis ͉ PTHrP ͉ senescence

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Section: Ntranuclear Transport Of Numerous Polypeptide Ligands Has mentioning

confidence: 99%

Severe growth retardation and early lethality in mice lacking the nuclear localization sequence and C-terminus of PTH-related protein

Miao

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

114

113

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“…However, Aarts and colleagues 36 demonstrated that the NLS-(87-107) alone was able to induce internalisation and nuclear localisation in chondrocytic cells. The differences between groups can be accounted for by the use of different cells lines, which is highlighted by differences seen in nuclear translocation of PTHrP-(1-34).…”

Section: Discussionmentioning

confidence: 99%

Nuclear targeting of a midregion PTHrP fragment is necessary for stimulating growth in breast cancer cells

Kumari

Robertson

Watson

2006

Intl Journal of Cancer

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Parathyroid-hormone related protein (PTHrP) is the primary factor in humoral hypercalcemia of malignancy and is highly secreted by breast cancers. The pro-hormone undergoes posttranslational processing and cleavage to give rise to mature secretory peptides, one of which is midregion PTHrP (38-94/95/101) containing a nuclear localisation sequence (NLS) in amino acids (87)(88)(89)(90)(91)(92)(93)(94)(95)(96)(97)(98)(99)(100)(101)(102)(103)(104)(105)(106). The current study investigates whether the NLS in midregion PTHrP is important in breast cancer growth. PTHrP-(67-101), a midregion PTHrP fragment containing NLS-(87-101) significantly increased growth of MCF-7 and MDA-MB231 cells (126.3 and 121.3% of control respectively in serum conditions), independent of PTHR1 whereas PTHrP-(67-86), which lacks the NLS did not. Fluorescent-labelled PTHrP-(67-101) translocated to the nucleus, whereas PTHrP-(67-86) remained cytosolic and a scrambled(1NLS) peptide was not internalised. In comparison, no growth influence or uptake was seen in non-tumour breast cells (Hs578Bst). Increases in intracellular calcium mobilisation were observed in breast cancer cells stimulated with both PTHrP-(67-101) and PTHrP-(67-86) (EC 50 of 3.2 pM and 2.2 pM respectively for MCF-7 cells), whereas inositide turnover was not detected. Both nuclear uptake and calcium signalling were attenuated in the presence of EGTA, but not with U73122 or N-terminal PTHrP peptides. Our studies indicate that the NLS-containing midregion PTHrP peptide is dependent on both internalisation and nuclear translocation to induce growth in breast cancer cells. These findings highlight the importance of midregion PTHrP and its receptor in breast cancer growth and may provide potential targets for future therapeutic intervention. ' 2006 Wiley-Liss, Inc.Key words: PTHrP; breast cancer; NLS; calcium signalling; midregion PTHrP Parathyroid hormone-related protein (PTHrP) was first identified as a tumour-derived protein that was the primary factor in humoral hypercalcemia of malignancy (HHM). 1-3 The first 13 amino acids of PTHrP and parathyroid hormone (PTH) share significant homology 4,5 and it is this sequence which interacts with the parathyroid hormone receptor 1 (PTHR1). 6 As a result, tumour-derived PTHrP enters the circulation and activates PTHR1 in both the bone and kidney to induce PTH-like activity, the outcome of which is hypercalcaemia and osteoclast-mediated bone resorption. 1,2,7 PTHrP is expressed in breast epithelium and is associated with normal mammary gland function, cell growth and differentiation. [8][9][10][11][12] Studies using PTHrP knockout mice resulted in mammary epithelial cell degeneration, 13 emphasising the importance of PTHrP in breast growth. Breast cancers, in most cases, secrete high levels of PTHrP, [14][15][16] and as a result malignancy associated HHM is very common. The expression of PTHrP has also been reported to be higher in breast cancer skeletal metastases than in the primary tumour. 14,17,18 The role of PTHrP may therefore be biolog...

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“…Although the presence of some other GPCRs at the nucleus has been reported (29, 46 -49), functionality has only been documented for PGE 2 and angiotensin II receptors (29,46,50); however, the latter peptide is not produced locally but possibly translocates to the nucleus as shown for parathyroid hormone and somatostatin (51,52). In contrast, PAF could be generated locally and act on its adjacent receptor in the nucleus (Figs.…”

Section: Discussionmentioning

confidence: 99%

Proinflammatory Gene Induction by Platelet-Activating Factor Mediated Via Its Cognate Nuclear Receptor

Marrache

Gobeil

Bernier

et al. 2002

The Journal of Immunology

115

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It has been postulated that intracellular binding sites for platelet-activating factor (PAF) contribute to proinflammatory responses to PAF. Isolated nuclei from porcine cerebral microvascular endothelial cells (PCECs) produced PAF-molecular species in response to H2O2. Using FACS analysis, we demonstrated the expression of PAF receptors on cell and nuclear surfaces of PCECs. Confocal microscopy studies performed on PCECs, Chinese hamster ovary cells stably overexpressing PAF receptors, and isolated nuclei from PCECs also showed a robust nuclear distribution of PAF receptors. Presence of PAF receptors at the cell nucleus was further revealed in brain endothelial cells by radioligand binding experiments, immunoblotting, and in situ in brain by immunoelectron microscopy. Stimulation of nuclei with methylcarbamate-PAF evoked a decrease in cAMP production and a pertussis toxin-sensitive rise in nuclear calcium, unlike observations in plasma membrane, which exhibited a pertussis toxin-insensitive elevation in inositol phosphates. Moreover, on isolated nuclei methylcarbamate-PAF evoked the expression of proinflammatory genes inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) and was associated with augmented extracellular signal-regulated kinase 1/2 phosphorylation and NF-κB binding to the DNA consensus sequence. COX-2 expression was prevented by mitogen-activated protein kinase kinase/extracellular signal-regulated kinase 1/2 and NF-κB inhibitors. This study describes for the first time the nucleus as a putative organelle capable of generating PAF and expresses its receptor, which upon stimulation induces the expression of the proinflammatory gene COX-2.

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The Nucleolar Targeting Signal (NTS) of Parathyroid Hormone Related Protein Mediates Endocytosis and Nucleolar Translocation

Cited by 87 publications

References 42 publications

Severe growth retardation and early lethality in mice lacking the nuclear localization sequence and C-terminus of PTH-related protein

Severe growth retardation and early lethality in mice lacking the nuclear localization sequence and C-terminus of PTH-related protein

Nuclear targeting of a midregion PTHrP fragment is necessary for stimulating growth in breast cancer cells

Proinflammatory Gene Induction by Platelet-Activating Factor Mediated Via Its Cognate Nuclear Receptor

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