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Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
Published on: June 13, 2014
LMBD1 protein serves as a specific adaptor for insulin receptor internalization
Linda Tzu-Ling Tseng1, Chieh-Liang Lin1, Kai-Yuan Tzen2
1From the Institute of Biochemistry and Molecular Biology.
The Journal of Biological Chemistry
|October 1, 2013
Summary
The LMBD1 protein regulates plasma membrane function and insulin receptor (IR) signaling. LMBD1 controls IR endocytosis, impacting cellular energy balance and disease pathways.
Area of Science:
- Cellular biology
- Molecular mechanisms of disease
- Membrane protein trafficking
Background:
- Energy homeostasis is vital for cellular function and disease prevention.
- The LMBD1 protein, encoded by lmbrd1, has 9 transmembrane domains and is implicated in lysosomal cobalamin export.
- LMBD1's role in plasma membrane regulation and its impact on cellular energy balance were investigated.
Purpose of the Study:
- To elucidate the function of LMBD1 in the plasma membrane.
- To determine LMBD1's role in regulating insulin receptor (IR) signaling and endocytosis.
- To investigate the impact of lmbrd1 gene modulation on cellular energy uptake.
Main Methods:
- Micro-positron emission tomography (PET) analysis in murine models.
- Western blotting and gene knockdown techniques.
- Confocal and live total internal reflection fluorescence microscopy.
- Mutation analysis and phenotypic rescue experiments.
Main Results:
- Knockout of lmbrd1 increased (18)F-fluorodeoxyglucose uptake in murine hearts.
- LMBD1 knockdown led to upregulated insulin receptor (IR) and Akt signaling.
- LMBD1 co-localized and co-internalized with clathrin and the IR, suggesting a role in clathrin-mediated endocytosis.
- LMBD1 interacts with adaptor protein-2 and selectively mediates IR endocytosis.
Conclusions:
- LMBD1 plays a critical regulatory role at the plasma membrane.
- LMBD1 is essential for the clathrin-mediated endocytosis and proper recycling of the insulin receptor (IR).
- Dysregulation of LMBD1 impairs IR signaling, affecting cellular energy homeostasis and potentially contributing to disease.
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