Mapping leptin-interacting sites in recombinant leptin-binding domain (LBD) subcloned from chicken leptin receptor

Niv-Spector, Leonora; Raver, N; Friedman-Einat, Miriam; Grosclaude, Jeanne; Gussakovsky, Eugene; Livnah, Oded; Gertler, Arieh

doi:10.1042/bj20050233

Cited by 56 publications

(45 citation statements)

References 35 publications

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“…The cross-species binding of CLEPR has been demonstrated both in modified cell cultures expressing exogenous CLEPR cDNA (Adachi et al 2008, Hen et al 2008 and by surface plasmon resonance assay using the recombinant leptin-binding domain of CLEPR (Niv-Spector et al 2005). These results are compatible with the high similarity in predicted tertiary structure between the mammalian leptin and the highly divergent Xenopus leptin (Crespi & Denver 2006).…”

Section: Discussionsupporting

confidence: 72%

“…Specific STAT3 phosphorylation and activation of the Janus kinase (JAK)-STAT pathway by CLEPR in vitro, similar to the signal transduction pathway characterized in mammals, were demonstrated in several cell culture systems (Adachi et al 2008). In addition, the recombinant predicted leptin-binding domain of CLEPR was shown to specifically bind leptins of several origins in vitro (Niv-Spector et al 2005).…”

Section: Introductionmentioning

confidence: 86%

“…Altogether, these demonstrations of conservation of CLEPR with respect to its structure, chromosomal position, expression pattern and biological activity (Dunn et al 2000, Horev et al 2000, Ohkubo et al 2000, Richards & Poch 2003, Niv-Spector et al 2005, Liu et al 2007, Adachi et al 2008, Hen et al 2008 could be considered as an indication of its function in vivo. However, the CLEPR ligand has not yet been found (Friedman-Einat et al 1999, Dunn et al 2001, Amills et al 2003, Sharp et al 2008, Pitel et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Yosefi

Hen²,

Rosenblum³

et al. 2010

Journal of Endocrinology

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Unsuccessful attempts to identify the leptin gene in birds are well documented, despite the characterization of its receptor (LEPR). Since leptin and LEPR have poor sequence conservation among vertebrates, we speculated that a functional assay should represent the best way to detect leptin in birds. Using a leptin bioassay that is based on activation of the chicken LEPR in cultured cells, blood samples from wild birds with extreme seasonal variation in voluntary food intake and fat deposition (Adélie penguins and bar-tailed godwits) were tested for leptin activity. In these experiments, blood samples collected during the pre-incubation and the chick-rearing periods of Adélie penguins, and during the migratory flight and refueling stages of bar-tailed godwits, were found to contain no detectable leptin activity, while the sensitivity of the assay to activation by human blood samples from donor subjects representing a variety of body mass indices and fat contents was clearly demonstrated. These results suggest that in birds, an alternative control mechanism to that of mammals operates in the communication between the body fat tissues and the central control on energy homeostasis.

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Section: Discussionsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Yosefi

Hen²,

Rosenblum³

et al. 2010

Journal of Endocrinology

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“…that used a recombinant fragment of CLEPR containing the leptin-binding domain (Niv-Spector et al 2005), and studies involving the administration of human leptin to chickens (Denbow et al 2000, Kuo et al 2005. However, some discrepancies exist within the later reports with respect to the possibility that chicken strains selected for rapid growth are leptin resistant, and with an additional publication (Bungo et al 1999) demonstrating nonresponsiveness of young chicks to administration of mouse leptin.…”

Section: Discussionmentioning

confidence: 95%

“…Given that the controversial chicken leptin is highly similar to mouse leptin (95% identical amino acids), it is not surprising that this recombinant preparation facilitated leptin-like activity in our bioassay (data not shown) and bound a recombinant fragment containing the leptin-binding domain of the CLEPR in vitro (Niv-Spector et al 2005). Administration of this leptin in chickens resulted in inhibition of food intake (Dridi et al 2000, Cassy et al 2004.…”

Section: Discussionmentioning

confidence: 99%

Monitoring leptin activity using the chicken leptin receptor

Hen¹,

Yosefi²,

Ronin³

et al. 2008

Journal of Endocrinology

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We report on the construction of a leptin bioassay based on the activation of chicken leptin receptor in cultured cells. A human embryonic kidney (HEK)-293 cell line, stably transfected with the full-length cDNA of chicken leptin receptor together with a STAT3-responsive reporter gene specifically responded to recombinant human and Xenopus leptins. The observed higher sensitivity of chicken leptin receptor to the former is in agreement with the degree of sequence similarity among these species (about 60 and 38% identical amino acids between humans and chickens, and between humans and Xenopus respectively). The specific activation of signal transduction through the chicken leptin receptor, shown here for the first time, suggests that the transition of Gln269 (implicated in the Gln-to-Pro Zucker fatty mutation in rats) to Glu in chickens does not impair its activity. Analysis of leptin-like activity in human serum samples of obese and lean subjects coincided well with leptin levels determined by RIA. Serum samples of pre-and post partum cows showed a tight correlation with the degree of adiposity. However, specific activation of the chicken leptin receptor in this assay was not observed with serum samples from broiler or layer chickens (representing fat and lean phenotypes respectively) or with those from turkey. Similar leptin receptor activation profiles were observed with cells transfected with human leptin receptor. Further work is needed to determine whether the lack of leptin-like activity in the chicken serum samples is due to a lack of leptin in this species or simply to a serum level of leptin that is below the detection threshold.

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Survey of the year 2005 commercial optical biosensor literature

2006

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We identified 1113 articles (103 reviews, 1010 primary research articles) published in 2005 that describe experiments performed using commercially available optical biosensors. While this number of publications is impressive, we find that the quality of the biosensor work in these articles is often pretty poor. It is a little disappointing that there appears to be only a small set of researchers who know how to properly perform, analyze, and present biosensor data. To help focus the field, we spotlight work published by 10 research groups that exemplify the quality of data one should expect to see from a biosensor experiment. Also, in an effort to raise awareness of the common problems in the biosensor field, we provide side-by-side examples of good and bad data sets from the 2005 literature.

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Mapping leptin-interacting sites in recombinant leptin-binding domain (LBD) subcloned from chicken leptin receptor

Cited by 56 publications

References 35 publications

Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Lack of leptin activity in blood samples of Adélie penguin and bar-tailed godwit

Monitoring leptin activity using the chicken leptin receptor

Survey of the year 2005 commercial optical biosensor literature

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