Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms
Lipid scrambling is a rapid process that dissipates the asymmetrical distribution of phospholipids in the plasma membrane. It is involved in various physiological functions such as blood coagulation and apoptosis. Many TMEM16 members are recognized as Ca<sup>2+</sup>-activated phospholip...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/12/10/1005 |
| _version_ | 1797471531891163136 |
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| author | Hanggu Kim Eunyoung Kim Byoung-Cheol Lee |
| author_facet | Hanggu Kim Eunyoung Kim Byoung-Cheol Lee |
| author_sort | Hanggu Kim |
| collection | DOAJ |
| description | Lipid scrambling is a rapid process that dissipates the asymmetrical distribution of phospholipids in the plasma membrane. It is involved in various physiological functions such as blood coagulation and apoptosis. Many TMEM16 members are recognized as Ca<sup>2+</sup>-activated phospholipid scramblases, which transport phospholipids between the two leaflets of the plasma membrane nonspecifically and bidirectionally; among these, TMEM16C is abundant in the brain, especially in neuronal cells. We investigated the scrambling activity of three human TMEM16C isoforms with different N-terminus lengths. After optimizing conditions to minimize endogenous scrambling activity, an annexin V-based imaging assay was used to detect phosphatidylserine (PS) scrambling in 293T cells. Unlike previous results, our data showed that human TMEM16C isoform 1 and isoform 3 exposed PS to the cell surface. A surface biotinylation assay showed that the surface expression of isoform 2, which did not show scrambling activity, was ~5 times lower than the other isoforms. In contrast to other TMEM16 proteins, flux assays and electrophysiology recording showed TMEM16C does not possess ion-transporting activity. We conclude that the N-terminus of TMEM16C determines whether TMEM16C can translocate to the plasma membrane and facilitate scrambling activity; membrane-localized TMEM16C isoforms 1 and 3 transport PS to the outer leaflet. |
| first_indexed | 2024-03-09T19:49:31Z |
| format | Article |
| id | doaj.art-b0780d59852e4345ac58f3cd2d77966b |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-09T19:49:31Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-b0780d59852e4345ac58f3cd2d77966b2023-11-24T01:14:09ZengMDPI AGMembranes2077-03752022-10-011210100510.3390/membranes12101005Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C IsoformsHanggu Kim0Eunyoung Kim1Byoung-Cheol Lee2Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu 41068, KoreaNeurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu 41068, KoreaNeurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu 41068, KoreaLipid scrambling is a rapid process that dissipates the asymmetrical distribution of phospholipids in the plasma membrane. It is involved in various physiological functions such as blood coagulation and apoptosis. Many TMEM16 members are recognized as Ca<sup>2+</sup>-activated phospholipid scramblases, which transport phospholipids between the two leaflets of the plasma membrane nonspecifically and bidirectionally; among these, TMEM16C is abundant in the brain, especially in neuronal cells. We investigated the scrambling activity of three human TMEM16C isoforms with different N-terminus lengths. After optimizing conditions to minimize endogenous scrambling activity, an annexin V-based imaging assay was used to detect phosphatidylserine (PS) scrambling in 293T cells. Unlike previous results, our data showed that human TMEM16C isoform 1 and isoform 3 exposed PS to the cell surface. A surface biotinylation assay showed that the surface expression of isoform 2, which did not show scrambling activity, was ~5 times lower than the other isoforms. In contrast to other TMEM16 proteins, flux assays and electrophysiology recording showed TMEM16C does not possess ion-transporting activity. We conclude that the N-terminus of TMEM16C determines whether TMEM16C can translocate to the plasma membrane and facilitate scrambling activity; membrane-localized TMEM16C isoforms 1 and 3 transport PS to the outer leaflet.https://www.mdpi.com/2077-0375/12/10/1005membrane proteinslipid transportscramblasesion channels |
| spellingShingle | Hanggu Kim Eunyoung Kim Byoung-Cheol Lee Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms Membranes membrane proteins lipid transport scramblases ion channels |
| title | Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms |
| title_full | Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms |
| title_fullStr | Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms |
| title_full_unstemmed | Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms |
| title_short | Investigation of Phosphatidylserine-Transporting Activity of Human TMEM16C Isoforms |
| title_sort | investigation of phosphatidylserine transporting activity of human tmem16c isoforms |
| topic | membrane proteins lipid transport scramblases ion channels |
| url | https://www.mdpi.com/2077-0375/12/10/1005 |
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