Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system
<p>Small heat shock proteins (sHsps) are a family of ubiquitous proteins that defend the first line for proteostasis. They have specific regulatory roles to fulfill their chaperone functions or maintain the physiological structures of tissues through interactions with their native or dysfuncti...
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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2021
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| _version_ | 1817931837935190016 |
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| author | Wang, Z |
| author2 | Benesch, J |
| author_facet | Benesch, J Wang, Z |
| author_sort | Wang, Z |
| collection | OXFORD |
| description | <p>Small heat shock proteins (sHsps) are a family of ubiquitous proteins that defend the first line for proteostasis. They have specific regulatory roles to fulfill their chaperone functions or maintain the physiological structures of tissues through interactions with their native or dysfunctional partners. This thesis will focus on the sHsps and their substrates in the human heart and skeletal muscles, using various biophysical and structural techniques to probe their structures and interactions. Among the sHsps, cardiovascular heat shock protein (cvHsp, HspB7) and HspB8 (Hsp22) perform their primary functions in cardiac tissues and skeletal muscles. Firstly, I find that, unlike the well-studied human sHsps like Hsp27 or αB-crystallin forming large oligomers based on dimeric building blocks, cvHsp is dominantly monomeric at dynamic conditions. I solve the crystal structure of cvHsp to explain that oligomerization and dimerization are much less favored for cvHsp. Then I study the actin-linking protein filamin C (FLNC) and confirm its dimerized domain 24 (d24) is the binding substrates of cvHsp. The monomeric cvHsp binds to the dimerized FLNCd24 and competes to its dimerization. This process can be regulated under stress conditions. Phosphorylation at FLNCd24 T2677 or Y2683 residues at different stress conditions has opposite effects in mediating the FLNC dimerization and interaction with cvHsp, which might be a potential target for mediating cancer development. To study this interaction at the atomic level, I reveal the binding surfaces for the cvHsp-FLNC interaction and obtain the crystal structure of the complex. cvHsp uses its β4 strand to bind FLNCd24 strand C, which is involved in the dimer interface. Some hydrophobic contacts within the interface make this interaction strong and specific. Both T2677 and Y2683 residues show up clearly in the structural analysis. We further research the FLNC clearance system, the chaperone-assisted selective autophagy (CASA) complex, which involves HspB8, BAG3, Hsp70, FLNC, and other components. We have obtained the stable construct of HspB8, and the purification of non-structured BAG3 is still going on. Overall, our studies provide new and deep insight into cardiac sHsps and their roles in maintaining proteostasis.</p> |
| first_indexed | 2024-03-06T18:31:38Z |
| format | Thesis |
| id | oxford-uuid:09d8466a-6c98-4d69-9a89-b67a514ce805 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-12-09T03:28:22Z |
| publishDate | 2021 |
| record_format | dspace |
| spelling | oxford-uuid:09d8466a-6c98-4d69-9a89-b67a514ce8052024-12-01T11:10:40ZCardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal systemThesishttp://purl.org/coar/resource_type/c_db06uuid:09d8466a-6c98-4d69-9a89-b67a514ce805EnglishHyrax Deposit2021Wang, ZBenesch, JStruwe, WThalassinos, K<p>Small heat shock proteins (sHsps) are a family of ubiquitous proteins that defend the first line for proteostasis. They have specific regulatory roles to fulfill their chaperone functions or maintain the physiological structures of tissues through interactions with their native or dysfunctional partners. This thesis will focus on the sHsps and their substrates in the human heart and skeletal muscles, using various biophysical and structural techniques to probe their structures and interactions. Among the sHsps, cardiovascular heat shock protein (cvHsp, HspB7) and HspB8 (Hsp22) perform their primary functions in cardiac tissues and skeletal muscles. Firstly, I find that, unlike the well-studied human sHsps like Hsp27 or αB-crystallin forming large oligomers based on dimeric building blocks, cvHsp is dominantly monomeric at dynamic conditions. I solve the crystal structure of cvHsp to explain that oligomerization and dimerization are much less favored for cvHsp. Then I study the actin-linking protein filamin C (FLNC) and confirm its dimerized domain 24 (d24) is the binding substrates of cvHsp. The monomeric cvHsp binds to the dimerized FLNCd24 and competes to its dimerization. This process can be regulated under stress conditions. Phosphorylation at FLNCd24 T2677 or Y2683 residues at different stress conditions has opposite effects in mediating the FLNC dimerization and interaction with cvHsp, which might be a potential target for mediating cancer development. To study this interaction at the atomic level, I reveal the binding surfaces for the cvHsp-FLNC interaction and obtain the crystal structure of the complex. cvHsp uses its β4 strand to bind FLNCd24 strand C, which is involved in the dimer interface. Some hydrophobic contacts within the interface make this interaction strong and specific. Both T2677 and Y2683 residues show up clearly in the structural analysis. We further research the FLNC clearance system, the chaperone-assisted selective autophagy (CASA) complex, which involves HspB8, BAG3, Hsp70, FLNC, and other components. We have obtained the stable construct of HspB8, and the purification of non-structured BAG3 is still going on. Overall, our studies provide new and deep insight into cardiac sHsps and their roles in maintaining proteostasis.</p> |
| spellingShingle | Wang, Z Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| title | Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| title_full | Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| title_fullStr | Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| title_full_unstemmed | Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| title_short | Cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| title_sort | cardiac small heat shock proteins and their roles in maintaining the integrity of the cytoskeletal system |
| work_keys_str_mv | AT wangz cardiacsmallheatshockproteinsandtheirrolesinmaintainingtheintegrityofthecytoskeletalsystem |