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Senescence marker protein 30 (SMP30) expression in eukaryotic cells: existence of multiple species and membrane localization.

ABSTRACT: Senescence marker protein (SMP30), also known as regucalcin, is a 34 kDa cytosolic marker protein of aging which plays an important role in intracellular Ca(2+) homeostasis, ascorbic acid biosynthesis, oxidative stress, and detoxification of chemical warfare nerve agents. In our goal to investigate the activity of SMP30 for the detoxification of nerve agents, we have produced a recombinant adenovirus expressing human SMP30 as a fusion protein with a hemaglutinin tag (Ad-SMP30-HA). Ad-SMP30-HA transduced the expression of SMP30-HA and two additional forms of SMP30 with molecular sizes ?28 kDa and 24 kDa in HEK-293A and C3A liver cells in a dose and time-dependent manner. Intravenous administration of Ad-SMP30-HA in mice results in the expression of all the three forms of SMP30 in the liver and diaphragm. LC-MS/MS results confirmed that the lower molecular weight 28 kDa and 24 kDa proteins are related to the 34 kDa SMP30. The 28 kDa and 24 kDa SMP30 forms were also detected in normal rat liver and mice injected with Ad-SMP30-HA suggesting that SMP30 does exist in multiple forms under physiological conditions. Time course experiments in both cell lines suggest that the 28 kDa and 24 kDa SMP30 forms are likely generated from the 34 kDa SMP30. Interestingly, the 28 kDa and 24 kDa SMP30 forms appeared initially in the cytosol and shifted to the particulate fraction. Studies using small molecule inhibitors of proteolytic pathways revealed the potential involvement of ? and ?-secretases but not calpains, lysosomal proteases, proteasome and caspases. This is the first report describing the existence of multiple forms of SMP30, their preferential distribution to membranes and their generation through proteolysis possibly mediated by secretase enzymes.

SUBMITTER: Arun P

PROVIDER: S-EPMC3036656 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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Senescence marker protein 30 (SMP30) expression in eukaryotic cells: existence of multiple species and membrane localization.

Arun Peethambaran P Aleti Vineela V Parikh Kalpana K Manne Veeraswamy V Chilukuri Nageswararao N

PloS one 20110209 2

Senescence marker protein (SMP30), also known as regucalcin, is a 34 kDa cytosolic marker protein of aging which plays an important role in intracellular Ca(2+) homeostasis, ascorbic acid biosynthesis, oxidative stress, and detoxification of chemical warfare nerve agents. In our goal to investigate the activity of SMP30 for the detoxification of nerve agents, we have produced a recombinant adenovirus expressing human SMP30 as a fusion protein with a hemaglutinin tag (Ad-SMP30-HA). Ad-SMP30-HA tr ...[more]

PMID: 21347421

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Project description:BackgroundSenescence marker protein 30 (SMP30), which plays a pivotal role as a suppressor protein in cell proliferation, among other regulatory actions, is a marker of aging that shows decreased expression during senescence. Decreased SMP30 has been identified in several human cancers, but its expression and role in human non-small cell lung cancer (NSCLC) remain unclear.MethodsUsing tumor tissue and matched adjacent normal tissue from 341 patients with resected NSCLC, we assessed SMP30 expression using immunohistochemical methods. The relationship between SMP30 expression and clinicopathologic characteristics was investigated by Kaplan-Meier survival analysis and multivariate analysis. Cell viability assay, colony formation assay, EdU incorporation assay and in vivo tumor xenograft models were also performed to investigate NSCLC cell proliferation using A549 and H1299 cell lines. Recombinant lentivirus-meditated in vivo gene overexpression and Western blot were performed to clarify the underlying molecular mechanism of SMP30 inhibiting NSCLC proliferation.ResultsSMP30 expression was frequently downregulated in NSCLC tissue, as compared with adjacent non-tumor tissue. Kaplan-Meier survival analyses revealed NSCLC patients with low SMP30 expression had a significantly worse overall survival (OS), with median OS of 18 vs. 67 months in high SMP30 expression group. SMP30 overexpression significantly inhibited A549 and H1299 cell proliferation both in vitro and in tumor xenografts and downregulated the expression of c-Myc and CyclinD1 protein. Moreover, Western blot analyses confirmed that SMP30 overexpression significantly inhibited the histone deacetylase 4 (HDAC4) level in NSCLC cells, and HDAC4 overexpression reversed SMP30-mediated NSCLC repression both in vitro and in vivo.ConclusionsSMP30 inhibited NSCLC proliferation by reducing HDAC4 expression, and SMP30 and HDAC4 may serve as new prognostic biomarkers and future therapeutic targets for NSCLC.

Dataset Information

Senescence marker protein 30 (SMP30) expression in eukaryotic cells: existence of multiple species and membrane localization.

Publications

Senescence marker protein 30 (SMP30) expression in eukaryotic cells: existence of multiple species and membrane localization.

Similar Datasets

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