THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR
Main Author: | |
---|---|
Language: | English |
Published: |
The Ohio State University / OhioLINK
2013
|
Subjects: | |
Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=osu1366356833 |
id |
ndltd-OhioLink-oai-etd.ohiolink.edu-osu1366356833 |
---|---|
record_format |
oai_dc |
collection |
NDLTD |
language |
English |
sources |
NDLTD |
topic |
Biochemistry Human prolactin human prolactin receptor prolactin receptor extracellular domain human growth hormone human prolactin receptor antagonists hormone receptor binding kinetics cytokine cytokine receptor receptor subdomains coupling motif |
spellingShingle |
Biochemistry Human prolactin human prolactin receptor prolactin receptor extracellular domain human growth hormone human prolactin receptor antagonists hormone receptor binding kinetics cytokine cytokine receptor receptor subdomains coupling motif Gordon, Timothy Jason THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR |
author |
Gordon, Timothy Jason |
author_facet |
Gordon, Timothy Jason |
author_sort |
Gordon, Timothy Jason |
title |
THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR |
title_short |
THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR |
title_full |
THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR |
title_fullStr |
THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR |
title_full_unstemmed |
THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR |
title_sort |
biological, structural and kinetic properties of prolactin, prolactin receptor antagonists, growth hormone and the prolactin receptor |
publisher |
The Ohio State University / OhioLINK |
publishDate |
2013 |
url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1366356833 |
work_keys_str_mv |
AT gordontimothyjason thebiologicalstructuralandkineticpropertiesofprolactinprolactinreceptorantagonistsgrowthhormoneandtheprolactinreceptor AT gordontimothyjason biologicalstructuralandkineticpropertiesofprolactinprolactinreceptorantagonistsgrowthhormoneandtheprolactinreceptor |
_version_ |
1719419242928930816 |
spelling |
ndltd-OhioLink-oai-etd.ohiolink.edu-osu13663568332021-08-03T05:22:27Z THE BIOLOGICAL, STRUCTURAL AND KINETIC PROPERTIES OF PROLACTIN, PROLACTIN RECEPTOR ANTAGONISTS, GROWTH HORMONE AND THE PROLACTIN RECEPTOR Gordon, Timothy Jason Biochemistry Human prolactin human prolactin receptor prolactin receptor extracellular domain human growth hormone human prolactin receptor antagonists hormone receptor binding kinetics cytokine cytokine receptor receptor subdomains coupling motif Human prolactin is a member of the class I cytokine family and is able to bind, activate and produce a biological response when associated with the human prolactin receptor. Prolactin has been shown to bind one prolactin receptor and undergo a conformational change in order to be available to bind a second prolactin receptor. Upon binding the second receptor, an active trimeric complex is formed and is able to produce a biological response. Specific locations on prolactin have been identified as binding sites for the first (site 1) and second (site 2) prolactin receptor and the order of binding to each of these receptors have been shown to be important. A coupling motif consisting of specific amino acids has been identified in human growth hormone upon receptor binding that allows for the binding of a second receptor. A similar motif has yet to be identified in human prolactin. I aimed to identify a similar coupling motif within human prolactin using mutagenesis. A coupling motif was unable to be identified, however, and binding of the second receptor at site 2 was shown to be very weak. A strong correlation was observed that links binding of the first receptor at site 1 with biological activity and was determined to be the event that activates the hormone/receptor complex. This observation was also made with growth hormone binding the prolactin receptor. Receptor binding growth hormone was seen to be the activating event and binding of the second prolactin receptor at site 2 was observed to be very weak. This model for receptor activation opposes the current model where both receptors need to bind the hormone with high affinity at both sites 1 and 2 in order to create an active trimeric complex. Prevention of a biological response produced by the prolactin receptor using receptor antagonists has utility as a pharmaceutical for cancers of the breast or prostate. A successful antagonist would be capable of binding a receptor in competition with in vivo hormone without inducing a biological response. Several receptor antagonists have been reported and works done by various groups to characterize these receptor antagonists have not been concise and the physical properties of each are unclear. I investigated several antagonists for their structural, biological, and kinetic properties. Several of these antagonists, including; ¿1-14, G129R, ¿41-52 and S179D, were each shown to not be successful antagonists because of instability and/or the induction of a biological response. One antagonist, ¿1-14/G129R, was shown to be structurally sound, did not induce a biological response, and was able to compete with wild-type prolactin to inhibit cell proliferation. This molecule was shown to have all the properties needed to be a successful receptor antagonist. The prolactin receptor extracellular domain contains regions that have been shown to be important for biological activity. The extracellular domain consists of two subdomains termed S1 and S2. Studies have shown that deletion of certain regions of the extracellular domain either inhibits receptor activation or creates constitutively active receptors in vivo. Regions of the receptor are thought to bind to adjacent regions and inhibit receptor activation. I have investigated each of the subdomains for their biological and kinetic properties. Each subdomain was not observed to bind prolactin suggesting that regions of both the S1 and S2 subdomains are required for hormone binding. The S2 subdomain was shown to not have an affinity for any region of the receptor or induce cell proliferation. The S1 subdomain has a high affinity for the extracellular domain of the prolactin receptor and a low affinity for the S1 subdomain. The S1 subdomain was also observed to have agonist activity in biological assays in the absence of hormone. The indication is that the S1 subdomain can bind regions of the extracellular domain and activate the receptor. Activation of the receptor by binding to these specific regions would suggest the presence of an inhibitory element that prevents activation. Binding to this inhibitory region frees this inhibition allowing the receptor to assume an active conformation and induce a biological response. 2013-08-06 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1366356833 http://rave.ohiolink.edu/etdc/view?acc_num=osu1366356833 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |