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Full-Text Articles in Medical Biochemistry
Could A Common Mechanism Of Protein Degradation Impairment Underlie Many Neurodegenerative Diseases?, David M. Smith
Could A Common Mechanism Of Protein Degradation Impairment Underlie Many Neurodegenerative Diseases?, David M. Smith
Faculty & Staff Scholarship
At the cellular level, many neurodegenerative diseases (NDs), often considered proteinopathies, are characterized by the accumulation of misfolded and damaged proteins into large insoluble aggregates. Prominent species that accumulate early and play fundamental roles in disease pathogenesis are amyloid β (Aβ) and tau in Alzheimer disease, α-synuclein (α-syn) in Parkinson disease, and polyQ-expanded huntingtin (Htt) in Huntington disease. Although significant efforts have focused on how the cell deals with these protein aggregates, why is it that these misfolded proteins are not degraded normally in the first place? A vast body of literature supports the notion that the cell’s protein degradation …
Experimental Intravascular Hemolysis Induces Hemodynamic And Pathological Pulmonary Hypertension: Association With Accelerated Purine Metabolism, Victor P. Bilan, Frank Schneider, Enrico M. Novelli, Eric E. Kelley, Sruti Shiva, Mark T. Gladwin, Edwin K. Jackson, Stevan P. Tofovic
Experimental Intravascular Hemolysis Induces Hemodynamic And Pathological Pulmonary Hypertension: Association With Accelerated Purine Metabolism, Victor P. Bilan, Frank Schneider, Enrico M. Novelli, Eric E. Kelley, Sruti Shiva, Mark T. Gladwin, Edwin K. Jackson, Stevan P. Tofovic
Faculty & Staff Scholarship
Pulmonary hypertension (PH) is emerging as a serious complication associated with hemolytic disorders, and plexiform lesions (PXL) have been reported in patients with sickle cell disease (SCD). We hypothesized that repetitive hemolysis per se induces PH and angioproliferative vasculopathy and evaluated a new mechanism for hemolysis-associated PH (HA-PH) that involves the release of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) from erythrocytes. In healthy rats, repetitive admin- istration of hemolyzed autologous blood (HAB) for 10 days produced reversible pulmonary parenchymal injury and vascular remodeling and PH. Moreover, the combination of a single dose of Sugen-5416 (SU, 200mg/kg) and 10-day …
Conformational Switching In The Coiled-Coil Domains Of A Proteasomal Atpase Regulates Substrate Processing, Aaron Snoberger, Evan J. Brettrager, David M. Smith
Conformational Switching In The Coiled-Coil Domains Of A Proteasomal Atpase Regulates Substrate Processing, Aaron Snoberger, Evan J. Brettrager, David M. Smith
Faculty & Staff Scholarship
Protein degradation in all domains of life requires ATPases that unfold and inject proteins into compartmentalized proteolytic chambers. Proteasomal ATPases in eukaryotes and archaea contain poorly understood N-terminally conserved coiled-coil domains. In this study, we engineer disulfide crosslinks in the coiled-coils of the archaeal proteasomal ATPase (PAN) and report that its three identical coiled-coil domains can adopt three different conforma- tions: (1) in-register and zipped, (2) in-register and partially unzipped, and (3) out-of-register. This conformational heterogeneity conflicts with PAN’s symmetrical OB-coiled-coil crystal structure but resembles the conformational heterogeneity of the 26S proteasomal ATPases’ coiled-coils. Furthermore, we find that one coiled-coil …
A Common Mechanism Of Proteasome Impairment By Neurodegenerative Disease-Associated Oligomers, Tiffany A. Thibaudeau, Raymond T. Anderson, David M. Smith
A Common Mechanism Of Proteasome Impairment By Neurodegenerative Disease-Associated Oligomers, Tiffany A. Thibaudeau, Raymond T. Anderson, David M. Smith
Faculty & Staff Scholarship
Protein accumulation and aggregation with a concomitant loss of proteostasis often con- tribute to neurodegenerative diseases, and the ubiquitin–proteasome system plays a major role in protein degradation and proteostasis. Here, we show that three different proteins from Alzheimer’s, Parkinson’s, and Huntington’s disease that misfold and oligomerize into a shared three-dimensional structure potently impair the proteasome. This study indicates that the shared conformation allows these oligomers to bind and inhibit the proteasome with low nanomolar affinity, impairing ubiquitin-dependent and ubiquitin-independent proteasome function in brain lysates. Detailed mechanistic analysis demonstrates that these oligomers inhibit the 20S proteasome through allosteric impairment of the …
Cone Phosphodiesterase-6Γ’ Subunit Augments Cone Pde6 Holoenzyme Assembly And Stability In A Mouse Model Lacking Both Rod And Cone Pde6 Catalytic Subunits, Wen-Tao Deng, Saravanan Kolandaivelu, Astra Dinculescu, Jie Li, Ping Zhu, Vince A. Chiodo, Visvanathan Ramamurthy, William W. Hauswirth
Cone Phosphodiesterase-6Γ’ Subunit Augments Cone Pde6 Holoenzyme Assembly And Stability In A Mouse Model Lacking Both Rod And Cone Pde6 Catalytic Subunits, Wen-Tao Deng, Saravanan Kolandaivelu, Astra Dinculescu, Jie Li, Ping Zhu, Vince A. Chiodo, Visvanathan Ramamurthy, William W. Hauswirth
Faculty & Staff Scholarship
Rod and cone phosphodiesterase 6 (PDE6) are key effector enzymes of the vertebrate phototransduction pathway. Rod PDE6 consists of two catalytic subunits PDE6α and PDE6β and two identical inhibitory PDE6γ subunits, while cone PDE6 is composed of two identical PDE6α’ catalytic subunits and two identical cone-specific PDE6γ’ inhibitory subunits. Despite their prominent function in regulating cGMP levels and therefore rod and cone light response properties, it is not known how each subunit contributes to the functional differences between rods and cones. In this study, we generated an rd10/cpfl1 mouse model lacking rod PDE6β and cone PDE6α’ subunits. Both rod and …