PXD066258-1

PXD066258 is an original dataset announced via ProteomeXchange.

Title	CRISPR activation screen uncovers MARCKSL1 as a gauge for extracellular vesicle secretion
Description	Extracellular vesicles (EVs) are crucial mediators of cell-cell communication that originate through one of two pathways: outward budding from the plasma membrane (PM) to yield microvesicles, or fusion of mature (late) endosomes with the PM for exosome release. How cells balance these two membrane pathways to optimize their EV repertoire remains unclear. To explore this, we performed a genome-wide CRISPR activation screen for genes that increase cell surface levels of the tetraspanin CD63—an EV marker that shuttles between late endosomes and the PM. Using this approach, we identified a membrane adaptor protein MARCKSL1 as a positive regulator of CD63 cell surface display. Follow-up ablation and overexpression studies demonstrated that MARCKSL1 potentiates EV secretion from the PM, in part at the expense of late endosome fusion with the PM. Mechanistically, we demonstrate that MARCKLS1 exploits its PM-binding effector domain to upregulate cell surface expression of CD63 and suppress late endosome—PM fusion. Furthermore, using proximity-based biotinylation proteomics, we identified the PM bridging protein Radixin and the SNARE-associated fusion component STXBP3 as key collaborators of MARCKSL1 in the context of PM homeostasis. Collectively, our findings reveal new mechanistic underpinnings of PM remodeling and implicate MARCKSL1 as a molecular gauge between different platforms for EV biogenesis.
HostingRepository	PRIDE
AnnounceDate	2026-06-18
AnnouncementXML	Submission_2026-06-18_03:05:40.880.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Rayman Tjokrodirijo
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: NEWT:9606;
ModificationList	acetylated residue; monohydroxylated residue; iodoacetamide derivatized residue
Instrument	Orbitrap Astral; Orbitrap Exploris 480

Revision	Datetime	Status	ChangeLog Entry
0	2025-07-17 03:28:38	ID requested
⏵ 1	2026-06-18 03:05:41	announced

Dataset with its publication pending

submitter keyword: Radixin,Extracellular vesicles, CD63, MARCKSL1, plasma membrane

Peter A. van Veelen
contact affiliation	Head Proteomics Group, Leiden University Medical Center, Center for Proteomics and Metabolomics, PO Box 9600, Postal zone P1-Q, 2300 RC Leiden, The Netherlands
contact email	P.A.van_Veelen@lumc.nl
lab head
Rayman Tjokrodirijo
contact affiliation	Leiden University Medical Center, Proteomics group
contact email	r.t.n.tjokrodirijo@lumc.nl
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD066258
     1. Label: PRIDE project
     2. Name: CRISPR activation screen uncovers MARCKSL1 as a gauge for extracellular vesicle secretion