{"entity": "researcher", "timestamp": "2026-08-22T06:57:36.424Z", "family": "Stefan", "given": "Christopher J", "initials": "CJ", "orcid": "0000-0002-4118-5721", "affiliations": ["MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom. c.stefan@ucl.ac.uk."], "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/researcher/847cba55d90a4c25af1d64b11e7617a0.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/researcher/847cba55d90a4c25af1d64b11e7617a0"}}, "publications": [{"entity": "publication", "iuid": "330fa93f26e446e48b850c8cba515fd2", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/330fa93f26e446e48b850c8cba515fd2.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/330fa93f26e446e48b850c8cba515fd2"}}, "title": "Tricalbin proteins regulate plasma membrane phospholipid homeostasis.", "authors": [{"family": "Thomas", "given": "Ffion B", "initials": "FB"}, {"family": "Omnus", "given": "Deike J", "initials": "DJ"}, {"family": "Bader", "given": "Jakob M", "initials": "JM", "orcid": "0000-0002-6575-0609", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1c53520521d344749c665414ed731224.json"}}, {"family": "Chung", "given": "Gary Hc", "initials": "GH", "orcid": "0000-0001-6764-3041", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/8ddd40f9e85749378aa4ab20557abdc2.json"}}, {"family": "Kono", "given": "Nozomu", "initials": "N", "orcid": "0000-0002-0871-8477", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/b21f66cdef544203ba698e640fae8ac7.json"}}, {"family": "Stefan", "given": "Christopher J", "initials": "CJ", "orcid": "0000-0002-4118-5721", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/847cba55d90a4c25af1d64b11e7617a0.json"}}], "type": "journal article", "published": "2022-08-00", "journal": {"title": "Life Sci. Alliance", "issn": "2575-1077", "volume": "5", "issue": "8", "issn-l": null}, "abstract": "The evolutionarily conserved extended synaptotagmin (E-Syt) proteins are calcium-activated lipid transfer proteins that function at contacts between the ER and plasma membrane (ER-PM contacts). However, roles of the E-Syt family members in PM lipid organisation remain incomplete. Among the E-Syt family, the yeast tricalbin (Tcb) proteins are essential for PM integrity upon heat stress, but it is not known how they contribute to PM maintenance. Using quantitative lipidomics and microscopy, we find that the Tcb proteins regulate phosphatidylserine homeostasis at the PM. Moreover, upon heat-induced membrane stress, Tcb3 co-localises with the PM protein Sfk1 that is implicated in PM phospholipid asymmetry and integrity. The Tcb proteins also control the PM targeting of the known phosphatidylserine effector Pkc1 upon heat-induced stress. Phosphatidylserine has evolutionarily conserved roles in PM organisation, integrity, and repair. We propose that phospholipid regulation is an ancient essential function of E-Syt family members required for PM integrity.", "doi": "10.26508/lsa.202201430", "pmid": "35440494", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC9018018"}, {"db": "pii", "key": "5/8/e202201430"}], "notes": [], "created": "2026-08-21T12:56:23.968Z", "modified": "2026-08-21T12:56:24.282Z"}, {"entity": "publication", "iuid": "0f2ad2ac24f548a0ac43af50367d0747", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/0f2ad2ac24f548a0ac43af50367d0747.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/0f2ad2ac24f548a0ac43af50367d0747"}}, "title": "A heat-sensitive Osh protein controls PI4P polarity.", "authors": [{"family": "Omnus", "given": "Deike J", "initials": "DJ"}, {"family": "Cadou", "given": "Angela", "initials": "A"}, {"family": "Thomas", "given": "Ffion B", "initials": "FB"}, {"family": "Bader", "given": "Jakob M", "initials": "JM"}, {"family": "Soh", "given": "Nathaniel", "initials": "N"}, {"family": "Chung", "given": "Gary H C", "initials": "GHC"}, {"family": "Vaughan", "given": "Andrew N", "initials": "AN"}, {"family": "Stefan", "given": "Christopher J", "initials": "CJ", "orcid": "0000-0002-4118-5721", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/847cba55d90a4c25af1d64b11e7617a0.json"}}], "type": "journal article", "published": "2020-03-13", "journal": {"title": "BMC Biol.", "issn": "1741-7007", "volume": "18", "issue": "1", "pages": "28", "issn-l": "1741-7007"}, "abstract": "Phosphoinositide lipids provide spatial landmarks during polarized cell growth and migration. Yet how phosphoinositide gradients are oriented in response to extracellular cues and environmental conditions is not well understood. Here, we elucidate an unexpected mode of phosphatidylinositol 4-phosphate (PI4P) regulation in the control of polarized secretion.\n\nWe show that PI4P is highly enriched at the plasma membrane of growing daughter cells in budding yeast where polarized secretion occurs. However, upon heat stress conditions that redirect secretory traffic, PI4P rapidly increases at the plasma membrane in mother cells resulting in a more uniform PI4P distribution. Precise control of PI4P distribution is mediated through the Osh (oxysterol-binding protein homology) proteins that bind and present PI4P to a phosphoinositide phosphatase. Interestingly, Osh3 undergoes a phase transition upon heat stress conditions, resulting in intracellular aggregates and reduced cortical localization. Both the Osh3 GOLD and ORD domains are sufficient to form heat stress-induced aggregates, indicating that Osh3 is highly tuned to heat stress conditions. Upon loss of Osh3 function, the polarized distribution of both PI4P and the exocyst component Exo70 are impaired. Thus, an intrinsically heat stress-sensitive PI4P regulatory protein controls the spatial distribution of phosphoinositide lipid metabolism to direct secretory trafficking as needed.\n\nOur results suggest that control of PI4P metabolism by Osh proteins is a key determinant in the control of polarized growth and secretion.", "doi": "10.1186/s12915-020-0758-x", "pmid": "32169085", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC7071650"}, {"db": "pii", "key": "10.1186/s12915-020-0758-x"}], "notes": [], "created": "2026-08-21T12:39:09.922Z", "modified": "2026-08-21T12:39:10.013Z"}]}