Conformational and receptor-binding properties of the insect neuropeptide proctolin and its analogues

1996 ◽  
Vol 10 (2) ◽  
pp. 89-99 ◽  
Author(s):  
Barbara Odell ◽  
Stephen J. Hammond ◽  
Richard Osborne ◽  
Michael W. Goosey
Keyword(s):  
Receptor Binding ◽  
Binding Properties ◽  
Insect Neuropeptide

Changes in cyclic AMP receptor properties during adaptation in Dictyostelium discoideum

1990 ◽  
Vol 95 (4) ◽  
pp. 623-629
Author(s):  
M.E. Luderus ◽  
M.J. Spijkers ◽  
R. Van Driel
Keyword(s):  
Cyclic Amp ◽  
G Protein ◽  
Dictyostelium Discoideum ◽  
Receptor Binding ◽  
Molecular Basis ◽  
Guanine Nucleotides ◽  
Cyclic Process ◽  
Binding Properties ◽  
Receptor System ◽  
Receptor Affinity

In developing Dictyostelium discoideum cells, binding of cyclic AMP to the chemotactic receptor has been shown to oscillate. These oscillations represent cycles of activation, adaptation and deadaptation of the cyclic AMP receptor system. We studied the molecular basis of these oscillatory changes in cyclic AMP receptor binding. We developed a rapid method of lysing cells during the course of the oscillations. This method guaranteed good preservation of ligand binding properties of the cyclic AMP receptor. We found that oscillations in cyclic AMP binding resulted from changes in receptor affinity. The total number of receptors did not significantly change during oscillations. Our experiments also showed that both GTP and GDP abolished oscillations in receptor binding completely, presumably by acting via a G protein. The guanine nucleotides reduced the affinity of the receptor at all time-points of the oscillation cycle to the minimal, i.e. adapted, level. We conclude that the cyclic process of activation, adaptation and de-adaptation in D. discoideum, at cyclic AMP receptor level, involves changes in receptor-G protein interaction. During adaptation, the affinity of the cyclic AMP receptor decreases and the receptor becomes insensitive to guanine nucleotides.

scholarly journals Mechanisms of fibroblast growth factor signaling in the ovarian follicle

2015 ◽  
Vol 228 (2) ◽  
pp. R31-R43 ◽  
Author(s):  
Christopher A Price
Keyword(s):  
Receptor Binding ◽  
Reproductive Tract ◽  
Ovarian Function ◽  
Ovarian Follicle ◽  
Female Reproductive Tract ◽  
Growth Factor Signaling ◽  
Fibroblast Growth ◽  
Fibroblast Growth Factor Signaling ◽  
Binding Properties ◽  
Differential Action

Fibroblast growth factors (FGFs) have been shown to alter growth and differentiation of reproductive tissues in a variety of species. Within the female reproductive tract, the effects of FGFs have been focused on the ovary, and the most studied one is FGF2, which stimulates granulosa cell proliferation and decreases differentiation (decreased steroidogenesis). Other FGFs have also been implicated in ovarian function, and this review summarizes the effects of members of two subfamilies on ovarian function; the FGF7 subfamily that also contains FGF10, and the FGF8 subfamily that also contains FGF18. There are data to suggest that FGF8 and FGF18 have distinct actions on granulosa cells, despite their apparent similar receptor binding properties. Studies of non-reproductive developmental biology also indicate that FGF8 is distinct from FGF18, and that FGF7 is also distinct from FGF10 despite similar receptor binding properties. In this review, the potential mechanisms of differential action of FGF7/FGF10 and FGF8/FGF18 during organogenesis will be reviewed and placed in the context of follicle development. A model is proposed in which FGF8 and FGF18 differentially activate receptors depending on the properties of the extracellular matrix in the follicle.

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