DOI: 10.5061/dryad.kprr4xhhz
title: Data from: Interactions between TTYH2 and APOE facilitate endosomal lipid transfer

description: Abstract The Tweety homologues (TTYHs) constitute a family of
 eukaryotic membrane proteins that, on the basis of structural features,
 were recently proposed to contribute to lipid transfer between soluble
 carriers and cellular membranes1. However, in the absence of supporting
 data, this function was hypothetical. Here through pull-down of endogenous
 proteins, we identify APOE as the interaction partner of human TTYH2.
 Subcellular fractionation and immunocytochemistry assays showed that both
 proteins colocalize in endosomal compartments. Characterization of the
 specific interaction between APOE and TTYH2 through binding assays and
 structural studies enabled us to identify an epitope in an extended domain
 of TTYH2 that faces the endosomal lumen. Structures of complexes with
 APOE-containing lipoprotein particles revealed a binding mode that places
 lipids in a suitable position to facilitate their diffusion into the
 membrane. Moreover, in vitro studies revealed that lipid transfer is
 accelerated by TTYH2. Collectively, our findings indicate that TTYH2 has a
 role in the unloading of APOE-containing lipoproteins after they are
 endocytosed. These results define a new protein class that facilitates the
 extraction of lipids from and their insertion into cellular membranes.
 Although ubiquitous, this process could be of particular relevance in the
 brain, where APOE is involved in the transfer of lipids between astrocytes
 and neurons.
description: # Data from: Interactions between TTYH2 and APOE facilitate endosomal
 lipid transfer Dataset DOI:
 [10.5061/dryad.kprr4xhhz](10.5061/dryad.kprr4xhhz) ## Description of the
 data and file structure Confocal microscopy images for: Interactions
 between TTYH2 and ApoE facilitate endosomal lipid transfer. Raw data for
 confocal microscopy images from Figure 2b, 2c; Extended Data Figure 3a-c;
 Extended Data Figure 9m. The .czi files contain stacks of images aquired
 from distinct areas using the ZEN software on a Zeiss LSM 980 Airyscan
 inverted confocal laser scanning microscope. The metadata for each file
 can be accessed by opening the files using FIJI -&gt; Image -&gt; Show
 info. The .czi files can be opened using FIJI. ### Files and variables
 #### File: Figure_2b.czi **Description:** Raw data for Figure 2b showing
 HEK293T cells stained with anti-TTYH2 antibody and DAPI. The primary
 purpose of the Figure 2b was to illustrate the intracellular localization
 of TTYH2. However, ApoE-mCherry lipoproteins were added to the cells prior
 to fixation at the concentration of 0.9 uM and incubation time of 20 min.
 Therefore, intracellular colocalization of the endocytosed ApoE-mCherry
 with TTYH2 can be observed in these data. #### File: Figure_2c.czi
 **Description:** Raw data for Figure 2c showing HEK293T cells stained with
 anti-TTYH2 antibody and DAPI that were exposed to ApoE-mCherry
 lipoproteins at concentration of 0.9 uM for 20 min prior to fixation.
 Colocalization of the endocytosed ApoE-mCherry with TTYH2 is observed.
 #### File: Extended_Data_Figure_3a.czi **Description:** Raw data for
 Extended Data Figure 3a showing HEK293T cells stained with anti-TTYH2
 antibody and DAPI that were exposed to ApoE-mCherry lipoproteins at
 concentration of 0.9 uM for 20 min prior to fixation. Colocalization of
 the endocytosed ApoE-mCherry with TTYH2 is observed. #### File:
 Extended_Data_Figure_3b.czi **Description:** Raw data for Extended Data
 Figure 3b showing HEK293T cells stained with anti-TTYH2 antibody,
 anti-Rab9 antibody, and DAPI. Colocalization of Rab9 and TTYH2 is
 observed. #### File: Extended_Data_Figure_3c.czi **Description:** Raw data
 for Extended Data Figure 3c showing HEK293T cells stained with anti-Rab9
 antibody, and DAPI that were exposed to ApoE-mCherry lipoproteins at
 concentration of 0.9 uM for 20 min prior to fixation. Colocalization of
 the endocytosed ApoE-mCherry with Rab9 is observed. #### File:
 Extended_Data_Figure_9m.czi **Description:** Raw data for Extended Data
 Figure 9m showing HEK293T cells stained with anti-TTYH2 antibody and DAPI
 that were exposed to ApoE lipoproteins loaded with 15% Rhodamine-labeled
 phosphatidylethanolamine at a concentration of 2 uM for 30 min before
 fixation. Colocalization of TTYH2 with lipids delivered through ApoE
 endocytosis is observed. ####