Dataset Information

Thinking outside the CaaX-box: an unusual reversible prenylation on ALDH9A1

ABSTRACT: Protein lipidation is a post-translational modification that confers hydrophobicity on protein substrates to control their cellular localization, mediate protein trafficking, and regulate protein function. In particular, protein prenylation is a C-terminal modification on proteins bearing canonical motifs catalyzed by prenyltransferases. Prenylated proteins have been of interest due to their numerous associations with various diseases. Chemical proteomic approaches have been pursued over the last decade to define prenylated proteomes (prenylome) and probe their responses to perturbations in various cellular systems. Here, we describe the discovery of prenylation of a non-canonical prenylated protein, ALDH9A1, which lacks any apparent prenylation motif. This enzyme was initially identified through chemical proteomic profiling of prenylomes in various cell lines. Metabolic labeling with an isoprenoid probe using overexpressed ALDH9A1 revealed that this enzyme can be prenylated inside cells but does not respond to inhibition by prenyltransferase inhibitors. Site-directed mutagenesis of the key residues involved in ALDH9A1 activity indicates that the catalytic C288 bears the isoprenoid modification likely through an NAD+-dependent mechanism. Furthermore, the isoprenoid modification is also susceptible to hydrolysis, indicating a reversible modification. We hypothesize that this modification originates from endogenous farnesal or geranygeranial, the established degradation products of prenylated proteins and results in a thioester form that accumulates. This novel reversible prenoyl modification on ALDH9A1 expands the current paradigm of protein prenylation by illustrating a potentially new type of protein–lipid modification that may also serve as a novel mechanism for controlling enzyme function

INSTRUMENT(S): Orbitrap Fusion Lumos, LTQ Orbitrap Elite

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell

SUBMITTER: Shelby Auger

LAB HEAD: Mark D

PROVIDER: PXD036365 | Pride | 2023-11-06

REPOSITORIES: Pride

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			Action	DRS
	CombinedmzTab.mzTab	Mztab
	Copy_of_KS_COS7_6plex_SPSMS3_Fusion_01292019_15_.raw	Raw
	Copy_of_KS_COS7_6plex_SPSMS3_Fusion_01292019_20_.raw	Raw
	Copy_of_KS_COS7_6plex_SPSMS3_Fusion_01292019_22_5_.raw	Raw
	Copy_of_KS_COS7_6plex_SPSMS3_Fusion_01292019_27_5_.raw	Raw

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Publications

Metabolic labeling with an alkyne probe reveals similarities and differences in the prenylomes of several brain-derived cell lines and primary cells.

Suazo Kiall F KF Jeong Angela A Ahmadi Mina M Brown Caroline C Qu Wenhui W Li Ling L Distefano Mark D MD

Scientific reports 20210223 1

Protein prenylation involves the attachment of one or two isoprenoid group(s) onto cysteine residues positioned near the C-terminus. This modification is essential for many signal transduction processes. In this work, the use of the probe C15AlkOPP for metabolic labeling and identification of prenylated proteins in a variety of cell lines and primary cells is explored. Using a single isoprenoid analogue, 78 prenylated protein groups from the three classes of prenylation substrates were identifie ...[more]

PMID: 33623102

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Project description:Plasmodium falciparum is the etiological agent of human malaria, one of the most widespread diseases in tropical and subtropical world regions. One of the biggest problems in controlling the disease is the emergence of drug resistance, which leads to the need to discover new antimalarial compounds. One of the most promissory drugs purposed is fosmidomycin, an inhibitor of the biosynthesis of isoprene units by the methylerythritol 4-phosphate (MEP) pathway which in some cases failed in clinic studies. Once formed, isoprene units are condensed to form longer structures such as farnesyl and geranylgeranyl pyrophosphate (GGPP), which are necessary for heme O and A formation, ubiquinone, and dolichyl phosphate biosynthesis as well as for protein isoprenylation. Even though the natural substrates of polyprenyl transferases and syntheses are polyprenyl pyrophosphates, it was already demonstrated that isoprenoid alcohols (polyprenols) such as farnesol (FOH) and geranylgeraniol (GGOH) can rescue parasites from fosmidomycin. This study better investigated how this rescue phenomenon occurs by performing drug-rescue assays. By this, it was observed that phytol (POH), a 20-carbon plant isoprenoid, rescues parasites from the fosmidomycin effect, similarly to FOH or GGOH. Contrarily, neither dolichols nor nonaprenol rescue parasites from fosmidomycin. Considering this, here we characterized the transport of FOH, GGOH, and POH. Once incorporated, it was observed that these substances are phosphorylated, condensed into longer isoprenoid alcohols, and incorporated into proteins and dolichyl phosphates. Through proteomic and radiolabelling approaches, it was found that prenylated proteins are naturally attached to several isoprenoids including GGOH, dolichol, and POH if exogenously added. Furthermore, results suggest the presence of at least two promiscuous protein prenyltransferases in the parasite: one enzyme which can use FPP among other unidentified substrates and another enzyme that can use GGOH, POH, and dolichols among other substrates not identified here. Thus, was obtained further evidence for dolichols and other isoprenoid products attached to proteins. This study helps better understand apicoplast-targeting antimalarials mechanism of action as well as novel posttranslational modifications of proteins.