86 research outputs found

    Transcriptional regulation of the urokinase receptor (u-PAR) - A central molecule of invasion and metastasis

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    The phenomenon of tumor-associated proteolysis has been acknowledged as a decisive step in the progression of cancer. This short review focuses on the urokinase receptor (u-PAR), a central molecule involved in tumor-associated invasion and metastasis, and summarizes the transcriptional regulation of u-PAR. The urokinase receptor (u-PAR) is a heavily glycosylated cell surface protein and binds the serine protease urokinase specifically and with high affinity. It consists of three similar cysteine-rich repeats and is anchored to the cell membrane via a GPI-anchor. The u-PAR gene comprises 7 exons and is located on chromosome 19q13. Transcriptional activation of the u-PAR promoter region can be induced by binding of transcription factors (Sp1, AP-1, AP-2, NF-kappaB). One current study gives an example for transcriptional downregulation of u-PAR through a PEA3/ets transcriptional silencing element. Knowledge of the molecular regulation of this molecule in tumor cells could be very important for diagnosis and therapy in the near future

    Thyroid control over biomembranes: VI. Lipids in liver mitochondria and microsomes of hypothyroid rats

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    The lipids of liver mitochondria prepared from normal rats and from rats made hypothyroid by thyroidectomy and injection with131INa contained similar amounts, per mg protein, of total lipids, phospholipids, neutral lipids and lipid phosphorus. Hypothyroidism caused a doubling of the relative amounts of mitochondrial cardiolipins (CL; to 20.5% of the phospholipid P) and an accompanying trend (although statistically not significant) toward decreased amounts of both phosphatidylcholines (PC) and phosphatidylserines (PS), with phosphatidylethanolamines (PE) remaining unchanged. The pattern of elevated 18∶2 fatty acyl content and depleted 20∶4 acyl groups of the mitochondrial phospholipids of hypothyroid preparations was reflected to varying degrees in the resolved phospholipids, with PC showing greater degrees of abnormality than PE, and CL showing none. Hypothyroidism produced the same abnormal pattern of fatty acyl distributions in liver microsomal total lipids as was found in the mitochondria. Hypothyroid rats, when killed 6 hr after injection of [1‐14C] labeled linoleate, showed the following abnormalities: the liver incorporated less label into lipids, and converted 18∶2 not exclusively to 20∶4 (as normals do) but instead incorporated the label mainly into saturated fatty acids. These data, together with the known decrease in β‐oxidation, suggest that hypothyroidism involves possible defective step(s) in the conversion of 18∶2 to 20∶4.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142296/1/lipd0328.pd

    Monitoring boreal forest biomass and carbon storage change by integrating airborne laser scanning, biometry and eddy covariance data

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    AbstractThis study presents a comparison and integration of three methods commonly used to estimate the amount of forest ecosystem carbon (C) available for storage. In particular, we examine the representation of living above- and below-ground biomass change (net accumulation) using plot-level biometry and repeat airborne laser scanning (ALS) of three dimensional forest plot structure. These are compared with cumulative net CO2 fluxes (net ecosystem production, NEP) from eddy covariance (EC) over a six-year period within a jack pine chronosequence of four stands (~94, 30, 14 and 3years since establishment from 2005) located in central Saskatchewan, Canada. Combining the results of the two methods yield valuable observations on the partitioning of C within ecosystems. Subtracting total living biomass C accumulation from NEP results in a residual that represents change in soil and litter C storage. When plotted against time for the stands investigated, the curve produced is analogous to the soil C dynamics described in Covington (1981). Here, ALS biomass accumulation exceeds EC-based NEP measured in young stands, with the residual declining with age as stands regenerate and litter decomposition stabilizes. During the 50–70year age-period, NEP and live biomass accumulation come into balance, with the soil and litter pools of stands 70–100years post-disturbance becoming a net store of C. Biomass accumulation was greater in 2008–2011 compared to 2005–2008, with the smallest increase in the 94-year-old “old jack pine” stand and greatest in the 14-year-old “harvested jack pine 1994” stand, with values of 1.4 (±3.2) tCha−1 and 12.0 (±1.6) tCha−1, respectively. The efficiency with which CO2 was stored in accumulated biomass was lowest in the youngest and oldest stands, but peaked during rapid regeneration following harvest (14-year-old stand). The analysis highlights that the primary source of uncertainty in the data integration workflow is in the calculation of biomass expansion factors, and this aspect of the workflow needs to be implemented with caution to avoid large error propagations. We suggest that the adoption of integrated ALS, in situ and atmospheric flux monitoring frameworks is needed to improve spatio-temporal partitioning of C balance components at sub-decadal scale within rapidly changing forest ecosystems and for use in national carbon accounting programs
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