Prenylation is a post-translational modification of proteins with isoprenoid substrates that plays a key role in cellular signaling and regulation. There are three types of prenylation: farnesylation, geranylgeranylation type I, and geranylgeranylation type II. Prenylation has been implicated in cancer, Alzheimer’s Disease, ALS, and fungal infections. Furthermore, farnesylation and geranylgeranylation have distinct roles in the development and pathology of these diseases. Proteomics has been a useful tool to identify prenylated proteins of interest in brain-related cells using an alkyne modified analogue of farnesyl diphosphate (FPP). This process currently identifies substrates for all three types of prenylation. Consequently, to further elucidate the specific role of both farnesylation and geranylgeranylation more selective methods are needed. Developed here are two alkyne-containing analogues of geranylgeranyl diphosphate (GGPP), the endogenous substrate for geranylgeranyltransferase, that are selective for the geranylgeranylation enzymes.  The first probe is C20AlkOPP has a twenty-carbon geranylgeranyl scaffold and was synthesized through a convergent synthesis and C15hAlkOPP has a fifteen-carbon farnesyl scaffold with an embedded homo propargyl alkyne.  Both probes are longer than FPP, making them unsuitable substrate for farnesyltransferase. Metabolic labeling experiments in COS7 cells demonstrated a difference in labeling between the GGPP analogues, the previously reported FPP analogue (C10AlkOPP), and total prenylation probe (C15AlkOPP) and proteomic analysis of COS7 cells treated with each probe showed identification of geranylgeranylated proteins.

Synthesis of novel isoprenoid analogues for proteomic analysis of the prenylome of geranylgeranylation

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.