New Approaches for the Identification of Drug Targets in Protozoan Parasites - International Review of Cell and Molecular Biology - page 367

It is important to keep in mind that changes in cellular organelles and tissue
structures seen at later time points during drug treatment are not necessar-
ily linked to the action of the compound itself, but often represent simply
general cell death-related alterations. Thus, corresponding assessments require
experienced personnel and are, again, often “subjective.” In addition, these
observations will rarely provide conclusive results with respect to a drug target
but can give an indication on which cellular processes are affected. Neverthe-
less, they may yield precious information for the discrimination of putative
drug targets identified by the strategies described below ( Table 7.3 ).

Table 7.3 Strategies for the identification of drug targets
Strategy Suitable organisms Input Output

Whole organism
analysis

All Intra- or extracel-

lular parasites
treated with
drug.

Spatiotemporal
effects on cellu-
lar and subcellu-
lar morphology.

Drug-affinity
chromatography

All Cell-free extracts,

soluble or
membrane
proteins.

Drug-binding
proteins.

Analysis of resis-
tant parasites

Parasites or parasite
stages allowing
in vitro culture
and analysis of
resistant strains.

Differential
genome or
transcriptome
analysis of
resistant clones.

Differentially
mutated or
regulated genes
in drug suscep-
tible vs resistant
strains.

Genome mining All parasites with

sequenced
genomes.

Class of well-
known target
proteins for a
given drug.

Recombinant pro-
teins expressed
e.g. in E. coli or
yeast for drug-
binding studies.

Reverse genetics All parasites that

allow over-
expression or
silencing of
genes.

Results from
drug-binding
studies with
recombinant
proteins and
from analysis of
resistant strains.

Overexpression of
drug receptors
or activators
enhances suscep-
tibility; overex-
pression of drug
metabolizers
enhances resis-
tance (silencing:
vice-versa).