Oliver Florey

Research Summary

Research in our lab is focused on the related topics of autophagy (self eating), macroendocytosis (digestion of extracellular material) and entosis (a recently discovered form of cell cannibalism). These are 3 distinct but inter-related forms of cellular ‘eating’, which play an important role in normal biology and become deregulated during ageing or disease (eg cancer).

Our work exploits a combination of molecular and cellular biology, state-of-the-art microscopy (long-term time-lapse imaging, spinning disk confocal and electron microscopy) and proteomics (mass spectrometry).

Existing projects aim to define the molecular mechanisms which underlie cellular eating, with a particular focus on the emerging pathway of non-canonical autophagy. We are also investigating the intriguing relationship between entosis and cancer.

Latest Publications

GABARAP sequesters the FLCN-FNIP tumor suppressor complex to couple autophagy with lysosomal biogenesis.
Goodwin JM, Walkup WG, Hooper K, Li T, Kishi-Itakura C, Ng A, Lehmberg T, Jha A, Kommineni S, Fletcher K, Garcia-Fortanet J, Fan Y, Tang Q, Wei M, Agrawal A, Budhe SR, Rouduri SR, Baird D, Saunders J, Kiselar J, Chance MR, Ballabio A, Appleton BA, Brumell JH, Florey O, Murphy LO

[Figure: see text].

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Science advances, 7, 40, Oct 2021

PMID: 34597140

A new flavor of cellular Atg8-family protein lipidation - alternative conjugation to phosphatidylserine during CASM.
Durgan J, Florey O

Atg8-family protein lipidation is the most commonly used marker for monitoring autophagy. During macroautophagy, Atg8-family proteins are specifically conjugated to phosphatidylethanolamine (PE) in forming, double-membrane autophagosomes. A distinct, non-canonical autophagy pathway also operates, characterized by the Conjugation of ATG8s to endolysosomal Single Membranes (CASM). In our new study, we show that CASM is associated with the alternative conjugation of Atg8-family proteins to phosphatidylserine (PS), and PE, in response to various cellular stimuli. We also discover differences in the regulation of conjugation to PE and PS by ATG4s, and altered dynamics between the two species. The identification of alternative Atg8-family protein PS lipidation opens up exciting new questions on the roles, regulation and biology of Atg8-family proteins during non-canonical autophagy.

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Autophagy, 1, 1, 12 Jul 2021

PMID: 34251968

Non-canonical autophagy drives alternative ATG8 conjugation to phosphatidylserine.
Durgan J, Lystad AH, Sloan K, Carlsson SR, Wilson MI, Marcassa E, Ulferts R, Webster J, Lopez-Clavijo AF, Wakelam MJ, Beale R, Simonsen A, Oxley D, Florey O

Autophagy is a fundamental catabolic process that uses a unique post-translational modification, the conjugation of ATG8 protein to phosphatidylethanolamine (PE). ATG8 lipidation also occurs during non-canonical autophagy, a parallel pathway involving conjugation of ATG8 to single membranes (CASM) at endolysosomal compartments, with key functions in immunity, vision, and neurobiology. It is widely assumed that CASM involves the same conjugation of ATG8 to PE, but this has not been formally tested. Here, we discover that all ATG8s can also undergo alternative lipidation to phosphatidylserine (PS) during CASM, induced pharmacologically, by LC3-associated phagocytosis or influenza A virus infection, in mammalian cells. Importantly, ATG8-PS and ATG8-PE adducts are differentially delipidated by the ATG4 family and bear different cellular dynamics, indicating significant molecular distinctions. These results provide important insights into autophagy signaling, revealing an alternative form of the hallmark ATG8 lipidation event. Furthermore, ATG8-PS provides a specific "molecular signature" for the non-canonical autophagy pathway.

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Molecular cell, 1, 1, 16 Apr 2021

PMID: 33909989

entosis and the formation of a cell-in-cell structure by MCF10A cells
A) Sequence of images showing entosis and the formation of a cell-in-cell structure by MCF10A cells in suspension. Cell 1 is engulfed by Cell 2.

B) H&E staining from a human breast carcinoma, arrows point to cell-in-cell structures (taken from Biomax.us).

C) Immunofluorescent staining of b-catenin in a cell-in-cell structure from a human breast tumor.

D) Immunofluorescent staining of E-cadherin in a cell-in-cell structure from MCF10A cells.