| 1. |
- Norlin, Stefan, et al.
(author)
-
Asna1/TRC40 Controls beta-Cell Function and Endoplasmic Reticulum Homeostasis by Ensuring Retrograde Transport
- 2016
-
In: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 65:1, s. 110-119
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Journal article (peer-reviewed)abstract
- Type 2 diabetes (T2D) is characterized by insulin resistance and beta-cell failure. Insulin resistance per se, however, does not provoke overt diabetes as long as compensatory beta-cell function is maintained. The increased demand for insulin stresses the beta-cell endoplasmic reticulum (ER) and secretory pathway, and ER stress is associated with beta-cell failure in T2D. The tail recognition complex (TRC) pathway, including Asna1/TRC40, is implicated in the maintenance of endomembrane trafficking and ER homeostasis. To gain insight into the role of Asna1/TRC40 in maintaining endomembrane homeostasis and beta-cell function, we inactivated Asnal in beta-cells of mice. We show that Asna1 beta(-/-) mice develop hypoinsulinemia, impaired insulin secretion, and glucose intolerance that rapidly progresses to overt diabetes. Loss of Asnal function leads to perturbed plasma membrane-to-trans Golgi network and Golgi-to-ER retrograde transport as well as to ER stress in beta-cells. Of note, pharmacological inhibition of retrograde transport in isolated islets and insulinoma cells mimicked the phenotype of Asna1(beta-/-) beta-cells and resulted in reduced insulin content and ER stress. These data support a model where Asnal ensures retrograde transport and, hence, ER and insulin homeostasis in beta-cells.
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|
| 2. |
- Norlin, Stefan, et al.
(author)
-
Asna1/TRC40 controls beta cell function and ER homeostasis by ensuring retrograde transport.
- 2016
-
In: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 65:1, s. 110-119
-
Journal article (peer-reviewed)abstract
- Type 2 diabetes (T2D) is characterized by insulin resistance and β-cell failure. Insulin resistance per se does, however, not provoke overt diabetes as long as compensatory β-cell function is maintained. The increased demand for insulin stresses the β-cell endoplasmic reticulum (ER) and secretory pathway, and ER stress is associated with β-cell failure in T2D. The tail-recognition complex (TRC) pathway, including Asna1/TRC40, is implicated in maintenance of endomembrane trafficking and ER homeostasis. To gain insight into the role for Asna1/TRC40 in maintenance of endomembrane homeostasis and β-cell function we inactivated Asna1 in β-cells of mice. Here, we show that Asna1(β-/-) mice develop hypoinsulinemia, impaired insulin secretion, and glucose intolerance that rapidly progresses to overt diabetes. Loss of Asna1 function leads to perturbed plasma membrane-to-TGN as well as Golgi-to-ER retrograde transport, and ER stress in β-cells. Intriguingly, pharmacological inhibition of retrograde transport in isolated islets and insulinoma cells mimicked the phenotype of Asna1(β-/-) β-cells and resulted in reduced insulin content and ER stress. Together, our data support a model where Asna1 ensures retrograde transport and hence ER and insulin homeostasis in β-cells.
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