Mechanisms of homomeric α1 glycine receptor endocytosis

Ren-Qi Huang, Shaoqing He, Zhenglan Chen, Glenn H. Dillon, Nancy J. Leidenheimer

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Abstract

Little is known regarding the mechanism(s) by which glycine receptors are endocytosed. Here we examined the endocytosis of homomeric α1 glycine receptors expressed in HEK 293 cells using immunofluorescence/confocal microscopy and whole-cell patch-clamp recordings. Our studies demonstrate that constitutive endocytosis of glycine receptors is blocked by the dominant negative dynamin construct K44A and that intracellular dialysis with peptide P4, a dynamin/amphiphysin-disrupting peptide, increased whole-cell glycine-gated chloride currents. To examine whether receptor endocytosis could be regulated by PKC, experiments with the PKC activator PMA (phorbol 12-myristate 13-acetate) were performed. PMA, but not its inactive analogue PMM (phorbol 12-monomyristate), stimulated receptor endocytosis and inhibited glycine-gated chloride currents. Similar to constitutive endocytosis, PKC-stimulated endocytosis was blocked by dynamin K44A. Mutation of a putative AP2 adaptin dileucine motif (L314A, L315A) present in the receptor cytoplasmic loop blocked PMA-stimulated receptor endocytosis and also prevented PMA inhibition of glycine receptor currents. In patch-clamp experiments, intracellular dialysis of a 12-amino acid peptide corresponding to the region of the receptor containing the dileucine motif prevented PKC modulation of wild-type glycine receptors. Unlike PKC modulation of the receptor, constitutive endocytosis was not affected by mutation of this dileucine motif. These results demonstrate that PKC activation stimulates glycine receptor endocytosis, that both constitutive endocytosis and PKC-stimulated endocytosis are dynamin-dependent, and that PKC-stimulated endocytosis, but not constitutive endocytosis, occurs via the dileucine motif (L314A, L315A) within the cytoplasmic loop of the receptor.

Original languageEnglish
Pages (from-to)11484-11493
Number of pages10
JournalBiochemistry
Volume46
Issue number41
DOIs
StatePublished - 16 Oct 2007

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Glycine Receptors
Endocytosis
Dynamins
Acetates
Dialysis
Clamping devices
Glycine
Chlorides
Modulation
Peptides
Confocal microscopy
Cytoplasmic and Nuclear Receptors
Experiments
Chemical activation
Amino Acids
phorbol-12-myristate
Mutation
HEK293 Cells
Fluorescence Microscopy
Confocal Microscopy

Cite this

Huang, R-Q., He, S., Chen, Z., Dillon, G. H., & Leidenheimer, N. J. (2007). Mechanisms of homomeric α1 glycine receptor endocytosis. Biochemistry, 46(41), 11484-11493. https://doi.org/10.1021/bi701093j
Huang, Ren-Qi ; He, Shaoqing ; Chen, Zhenglan ; Dillon, Glenn H. ; Leidenheimer, Nancy J. / Mechanisms of homomeric α1 glycine receptor endocytosis. In: Biochemistry. 2007 ; Vol. 46, No. 41. pp. 11484-11493.
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Huang, R-Q, He, S, Chen, Z, Dillon, GH & Leidenheimer, NJ 2007, 'Mechanisms of homomeric α1 glycine receptor endocytosis', Biochemistry, vol. 46, no. 41, pp. 11484-11493. https://doi.org/10.1021/bi701093j

Mechanisms of homomeric α1 glycine receptor endocytosis. / Huang, Ren-Qi; He, Shaoqing; Chen, Zhenglan; Dillon, Glenn H.; Leidenheimer, Nancy J.

In: Biochemistry, Vol. 46, No. 41, 16.10.2007, p. 11484-11493.

Research output: Contribution to journalArticleResearchpeer-review

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AU - Huang, Ren-Qi

AU - He, Shaoqing

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AU - Dillon, Glenn H.

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