AMPA receptor complex constituents: Control of receptor assembly, membrane trafficking and subcellular localization

2018 ◽  
Vol 91 ◽  
pp. 67-75 ◽  
Author(s):  
Eric Jacobi ◽  
Jakob von Engelhardt
Keyword(s):  
Subcellular Localization ◽  
Ampa Receptor ◽  
Membrane Trafficking ◽  
Receptor Complex ◽  
Receptor Assembly

scholarly journals Glycosylation Modulates Plasma Membrane Trafficking of CD24 in Breast Cancer Cells

2021 ◽  
Vol 22 (15) ◽  
pp. 8165
Author(s):  
Amanda Chantziou ◽  
Kostas Theodorakis ◽  
Hara Polioudaki ◽  
Eelco de Bree ◽  
Marilena Kampa ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plasma Membrane ◽  
Subcellular Localization ◽  
Cancer Cells ◽  
Membrane Trafficking ◽  
Breast Cancer Cells ◽  
Endocytic Pathway ◽  
Cell Periphery ◽  
Wild Type ◽  
Mcf 7

In breast cancer, expression of Cluster of Differentiation 24 (CD24), a small GPI-anchored glycoprotein at the cell periphery, is associated with metastasis and immune escape, while its absence is associated with tumor-initiating capacity. Since the mechanism of CD24 sorting is unknown, we investigated the role of glycosylation in the subcellular localization of CD24. Expression and localization of wild type N36- and/or N52-mutated CD24 were analyzed using immunofluorescence in luminal (MCF-7) and basal B (MDA-MB-231 and Hs578T) breast cancer cells lines, as well as HEK293T cells. Endogenous and exogenously expressed wild type and mutated CD24 were found localized at the plasma membrane and the cytoplasm, but not the nucleoplasm. The cell lines showed different kinetics for the sorting of CD24 through the secretory/endocytic pathway. N-glycosylation, especially at N52, and its processing in the Golgi were critical for the sorting and expression of CD24 at the plasma membrane of HEK293T and basal B type cells, but not of MCF-7 cells. In conclusion, our study highlights the contribution of N-glycosylation for the subcellular localization of CD24. Aberrant N-glycosylation at N52 of CD24 could account for the lack of CD24 expression at the cell surface of basal B breast cancer cells.

scholarly journals Deletion of olfactomedin 2 induces changes in the AMPA receptor complex and impairs visual, olfactory, and motor functions in mice

2014 ◽  
Vol 261 ◽  
pp. 802-811 ◽  
Author(s):  
Afia Sultana ◽  
Naoki Nakaya ◽  
Lijin Dong ◽  
Mones Abu-Asab ◽  
Haohua Qian ◽  
...  
Keyword(s):  
Ampa Receptor ◽  
Receptor Complex ◽  
Motor Functions

scholarly journals Fate of surrogate light chains in B lineage cells.

1996 ◽  
Vol 183 (2) ◽  
pp. 421-429 ◽  
Author(s):  
K Lassoued ◽  
H Illges ◽  
K Benlagha ◽  
M D Cooper
Keyword(s):  
B Cells ◽  
Cell Surface ◽  
Light Chain ◽  
Light Chains ◽  
Receptor Complex ◽  
Surrogate Light Chain ◽  
Heavy Chains ◽  
Receptor Component ◽  
B Lineage ◽  
Receptor Assembly

Biosynthesis of the immunoglobulin (Ig) receptor components and their assembly were examined in cell lines representative of early stages in human B lineage development. In pro-B cells, the nascent surrogate light chain proteins form a complex that transiently associates in the endoplasmic reticulum with a spectrum of unidentified proteins (40, 60, and 98 kD) and Bip, a heat shock protein family member. Lacking companion heavy chains, the surrogate light chains in pro-B cells do not associate with either the Ig(alpha) or Ig(beta) signal transduction units, undergo rapid degradation, and fail to reach the pro-B cell surface. In pre-B cells, by contrast, a significant portion of the surrogate light chain proteins associate with mu heavy chains, Ig(alpha), and Ig(beta) to form a stable receptor complex with a relatively long half-life. Early in this assembly process, Bip/GRP78, calnexin, GRP94, and a protein of approximately 17 kD differentially bind to the nascent mu heavy chains. The 17-kD intermediate is gradually replaced by the surrogate light chain protein complex, and the Ig(alpha) and Ig(beta) chains bind progressively to the mu heavy chains during the complex and relatively inefficient process of pre-B receptor assembly. The results suggest that, in humans, heavy chain association is essential for surrogate light chain survival and transport to the cell surface as an integral receptor component.

Molecular heterogeneity of calcium channel β-subunits in canine and human heart: evidence for differential subcellular localization

2004 ◽  
Vol 17 (2) ◽  
pp. 183-200 ◽  
Author(s):  
Jason D. Foell ◽  
Ravi C. Balijepalli ◽  
Brian P. Delisle ◽  
Anne Marie R. Yunker ◽  
Seth L. Robia ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Functional Properties ◽  
Membrane Trafficking ◽  
Sequence Data ◽  
Splice Variants ◽  
Ionic Current ◽  
Left Ventricular ◽  
Molecular Heterogeneity ◽  
Β Subunit ◽  
Western Blots

Multiple Ca2+ channel β-subunit (Cavβ) isoforms are known to differentially regulate the functional properties and membrane trafficking of high-voltage-activated Ca2+ channels, but the precise isoform expression pattern of Cavβ subunits in ventricular muscle has not been fully characterized. Using sequence data from the Human Genome Project to define the intron/exon structure of the four known Cavβ genes, we designed a systematic RT-PCR strategy to screen human and canine left ventricular myocardial samples for all known Cavβ isoforms. A total of 18 different Cavβ isoforms were detected in both canine and human ventricles including splice variants from all four Cavβ genes. Six of these isoforms have not previously been described. Western blots of ventricular membrane fractions and immunocytochemistry demonstrated that all four Cavβ subunit genes are expressed at the protein level, and the Cavβ subunits show differential subcellular localization with Cavβ1b, Cavβ2, and Cavβ3 predominantly localized to the T-tubule sarcolemma, whereas Cavβ1a and Cavβ4 are more prevalent in the surface sarcolemma. Coexpression of the novel Cavβ2c subunits (Cavβ2cN1, Cavβ2cN2, Cavβ2cN4) with the pore-forming α1C (Cav1.2) and Cavα2δ subunits in HEK 293 cells resulted in a marked increase in ionic current and Cavβ2c isoform-specific modulation of voltage-dependent activation. These results demonstrate a previously unappreciated heterogeneity of Cavβ subunit isoforms in ventricular myocytes and suggest the presence of different subcellular populations of Ca2+ channels with distinct functional properties.

Exendin-4 promotes the membrane trafficking of the AMPA receptor GluR1 subunit and ADAM10 in the mouse neocortex

2014 ◽  
Vol 190-191 ◽  
pp. 1-11 ◽  
Author(s):  
Nobuaki Ohtake ◽  
Mieko Saito ◽  
Masaaki Eto ◽  
Kenjiro Seki
Keyword(s):  
Ampa Receptor ◽  
Membrane Trafficking ◽  
Glur1 Subunit

scholarly journals AMPA Receptor Auxiliary Proteins of the CKAMP Family

2019 ◽  
Vol 20 (6) ◽  
pp. 1460 ◽  
Author(s):  
Jakob von Engelhardt
Keyword(s):  
Subcellular Localization ◽  
Ampa Receptor ◽  
Expression Profile ◽  
Ampa Receptors ◽  
Family Members ◽  
Interacting Proteins ◽  
Receptor Function ◽  
Cystine Knot ◽  
And Function

α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are assembled of four core subunits and several additional interacting proteins. Cystine-knot AMPA receptor-modulating proteins (CKAMPs) constitute a family of four proteins that influence the trafficking, subcellular localization and function of AMPA receptors. The four CKAMP family members CKAMP39/shisa8, CKAMP44/shisa9, CKAMP52/shisa6 and CKAMP59/shisa7 differ in their expression profile and their modulatory influence on AMPA receptor function. In this review, I report about recent findings on the differential roles of CKAMP family members.

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