Several hematopoietic growth factors (HGFs) have achieved widespread clinical
application. In the United States alone, more than US $5 billion per year of the health care
budget is spent on these factors. The first patients were treated with recombinant human
erythropoietin (rHuEPO, epoetin alfa, Epogen®) in 1985 and the first patients received
recombinant methionyl human granulocyte colony-stimulating factor (r-metHuG-CSF,
filgrastim, Neupogen®) or recombinant human granulocyte-macrophage colonystimulating
factor (rHuGM-CSF, sargramostim, Leukine® or Prokine®) in 1986.
Thrombopoietin is the primary regulator of platelet production. We exploi-ted two naturally occurring miniproteins of the inhibitor cystine knot fam-ily as stable and rigid scaffolds for the incorporation of peptide sequences
that have been shown to act as high-affinity thrombopoietin antagonists.
Several miniproteins that antagonistically block thrombopoietin-mediated
receptor activation were identified using a microscale reporter assay.
BH3 interacting domain death agonist (Bid), a pro-apoptotic member of
the Bcl-2 family of proteins, is activated through cleavage by caspase-8.
The active C-terminal fragment of Bid (tBid) translocates to the mitochon-dria where it interacts with cardiolipins at contact sites and induces the
release of cytochromecby a mechanism that is not yet fully understood.
Formyl peptide receptor-like 1 (FPRL1) is a seven transmembrane domain,
G protein-coupled receptor that interacts with a variety of exogenous and
host-derived agonists. In order to identify domains crucial for ligand recog-nition by FPRL1, we used chimeric receptors with segments in FPRL1
replaced by corresponding amino acid sequences derived from the proto-type formyl peptide receptor FPR. The chimeric receptors were stably
transfected into human embryonic kidney epithelial cells and the capacity
of the cells to migrate in response to formyl peptide receptor agonists was
Defining how the agonist–receptor interaction differs from
that of the antagonist–receptor and understanding the
mechanisms of receptor activation are fundamental issues in
cell signalling. The V1a vasopressin receptor (V1aR) is a
member of a family of related G-protein coupled receptors
that are activated by neurohypophysial peptide hormones,
including vasopressin (AVP). It has recently been reported
that anarginyl in the distalN-terminus of theV1a
for binding agonists but not antagonists....
A central pathway through which leptin acts to regulate appetite and body weight. Leptin signals through proopiomelanocortin (POMC) neurons in the hypothalamus to induce increased production of α-melanocyte-stimulating hormone (α-MSH), requiring the processing enzyme PC-1 (proenzyme convertase 1). α-MSH acts as an agonist on melanocortin-4 receptors to inhibit appetite, and
the neuropeptide AgRp (Agouti-related peptide) acts as an antagonist of this receptor. Mutations that cause obesity in humans are indicated by the solid green arrows.
The cloned guinea-pig Y2 neuropeptide Y (NPY) receptors expressed in Chinese hamster ovary (CHO) cells, as well as the Y2 receptors natively expressed in rat forebrain, are distributed in two populations. A smaller population that is readily accessed by agonist peptides on the surface of intact cells constitutes less than 30% of Y2 receptors detected in particulates after cell homogenization. A much larger fraction of cell surface Y2 sites can be activated by sulfhydryl modiﬁers.
In order to study the role of peroxisome proliferator-acti-vated receptor ain mouse intestine, its agonist-induced
proteins were identified by peptide mass fingerprinting fol-lowed byNorthern blot analysis using their cDNAs. One of
the most remarkably induced proteins was identified as
17b-hydroxysterol dehydrogenase type 11. Its very rapid
induction by various agonists was most efficient in intestine
and then in liver.