{"id":232965,"date":"2026-03-10T15:15:35","date_gmt":"2026-03-10T20:15:35","guid":{"rendered":"https:\/\/lifeboat.com\/blog\/2026\/03\/reversible-one-way-lipid-transfer-at-er-autophagosome-membrane-contact-sites-via-atg2"},"modified":"2026-03-10T15:15:35","modified_gmt":"2026-03-10T20:15:35","slug":"reversible-one-way-lipid-transfer-at-er-autophagosome-membrane-contact-sites-via-atg2","status":"publish","type":"post","link":"https:\/\/lifeboat.com\/blog\/2026\/03\/reversible-one-way-lipid-transfer-at-er-autophagosome-membrane-contact-sites-via-atg2","title":{"rendered":"Reversible one-way lipid transfer at ER\u2013autophagosome membrane contact sites via Atg2"},"content":{"rendered":"<p style=\"padding-right: 20px\"><a class=\"aligncenter blog-photo\" href=\"https:\/\/lifeboat.com\/blog.images\/reversible-one-way-lipid-transfer-at-er-autophagosome-membrane-contact-sites-via-atg2.gif\"><\/a><\/p>\n<p>Li Hao, Kuninori Suzuki et al. (University of Tokyo \u6771\u4eac\u5927\u5b66\u5927\u5b66\u9662\u65b0\u9818\u57df\u5275\u6210\u79d1\u5b66\u7814\u7a76\u79d1) report that lipophilic dye octadecyl rhodamine B (R18) is transported to the ER mediated by membrane transfer proteins. During autophagy, ER-resident R18 is transferred to the autophagic membrane via Atg2. After termination, R18 is reversed back to the ER, showing that the direction of bridge-type lipid transfer is modulated by metabolic states.<\/p>\n<hr>\n<p>Bridge-like lipid transfer proteins (LTPs) contain a repeating \u03b2-groove domain and long hydrophobic grooves that act as bridges at membrane contact sites (MCSs) to efficiently transfer lipids. Atg2 is one such bridge-like LTP essential for autophagosome formation, during which a newly synthesized isolation membrane (IM) emerges and expands through lipid supply. However, studies on Atg2-mediated lipid transfer are limited to <em>in vitro<\/em> studies due to the lack of a suitable probe for monitoring phospholipid dynamics <em>in vivo<\/em>. Here, we characterized the lipophilic dye octadecyl rhodamine B (R18), which internalizes and labels the endoplasmic reticulum (ER) in a manner that requires flippases and oxysterol-binding protein\u2013related proteins. Using R18, we demonstrated phospholipid transfer from the ER to the IM during autophagy <em>in vivo<\/em>. Upon autophagy termination, our data suggested the reversible phospholipid flow from the IM to the ER in response to environmental changes. Our findings highlight the critical role of bridge-like LTPs in MCS-mediated phospholipid homeostasis.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Li Hao, Kuninori Suzuki et al. (University of Tokyo \u6771\u4eac\u5927\u5b66\u5927\u5b66\u9662\u65b0\u9818\u57df\u5275\u6210\u79d1\u5b66\u7814\u7a76\u79d1) report that lipophilic dye octadecyl rhodamine B (R18) is transported to the ER mediated by membrane transfer proteins. During autophagy, ER-resident R18 is transferred to the autophagic membrane via Atg2. After termination, R18 is reversed back to the ER, showing that the direction of bridge-type [\u2026]<\/p>\n","protected":false},"author":662,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[],"class_list":["post-232965","post","type-post","status-publish","format-standard","hentry","category-futurism"],"_links":{"self":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/232965","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/users\/662"}],"replies":[{"embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/comments?post=232965"}],"version-history":[{"count":0,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/posts\/232965\/revisions"}],"wp:attachment":[{"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/media?parent=232965"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/categories?post=232965"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lifeboat.com\/blog\/wp-json\/wp\/v2\/tags?post=232965"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}