PXD018268

PXD018268 is an original dataset announced via ProteomeXchange.

Title	Alt-RPL36 downregulates the PI3K-AKT-mTOR signaling pathway by interacting with TMEM24
Description	While thousands of previously unannotated small and alternative open reading frames (alt-ORFs) have recently been revealed in the human genome, the functions of only a handful are currently known, leaving open the question of their biological significance as a class. Using a proteomic strategy for discovery of unannotated short open reading frames in human cells, we report the detection of alt-RPL36, a 148-amino acid protein co-encoded with and overlapping human RPL36. Alt-RPL36 interacts with TMEM24, which transports the phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] precursor phosphatidylinositol from the endoplasmic reticulum to the plasma membrane. Knock-out of alt-RPL36 in HEK 293T cells increased PI(4,5)P2 levels in the plasma membrane and upregulated the PI3K-AKT-mTOR signaling pathway. Remarkably, we find that four serine residues of alt-RPL36 are phosphorylated, and mutation of these four serines to alanine abolished the interaction with TMEM24 and regulation of PI3K signaling. These results implicate alt-RPL36 as a novel regulator of PI(4,5)P2 synthesis upstream of the PI3K-AKT-mTOR signaling pathway, and the first example of a phosphorylated alt-ORF product. More broadly, both alt-RPL36 and RPL36 regulate protein synthesis and cell growth via different molecular mechanisms – AKT signaling and ribosome composition, respectively. One human transcript can therefore express two sequence-independent polypeptides from overlapping ORFs that regulate the same processes via distinct mechanisms.
HostingRepository	PRIDE
AnnounceDate	2020-12-07
AnnouncementXML	Submission_2020-12-06_23:41:52.xml
DigitalObjectIdentifier	https://dx.doi.org/10.6019/PXD018268
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Supported dataset by repository
PrimarySubmitter	Alexandra Khitun
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	phosphorylated residue; acetylated residue; monohydroxylated residue
Instrument	Q Exactive HF; LTQ Orbitrap Velos

Revision	Datetime	Status	ChangeLog Entry
0	2020-03-30 05:20:39	ID requested
⏵ 1	2020-12-06 23:41:53	announced

Dataset with its publication pending

submitter keyword: human microprotein alt-protein phosphoproteomics

Sarah Ann Slavoff
contact affiliation	Department of Chemistry, Yale University West Campus Chemical Biology Institute
contact email	sarah.slavoff@yale.edu
lab head
Alexandra Khitun
contact affiliation	Harvard Medical School
contact email	Alexandra_Khitun@hms.harvard.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD018268
     1. Label: PRIDE project
     2. Name: Alt-RPL36 downregulates the PI3K-AKT-mTOR signaling pathway by interacting with TMEM24