An antiproliferative genetic screening identifies a peptide aptamer that targets calcineurin and up-regulates its activity.
Peptide aptamers are combinatorial recognition molecules that consist of a constant scaffold protein displaying a doubly constrained variable peptide loop. They bind specifically target proteins and interfere with their function. We have built a peptide aptamer library in a lentiviral expression system to isolate aptamers that inhibit cell proliferation in vitro. Using one of the isolated aptamers (R5G42) as a bait protein, we have performed yeast two-hybrid screening of cDNA libraries and identified calcineurin A as a target protein candidate. R5G42 bound calcineurin A in vitro and stimulated its phosphatase activity. When expressed transiently in human cells, R5G42 induced the dephosphorylation of BAD. We have identified an antiproliferative peptide aptamer that binds calcineurin and stimulates its activity. The use of this ligand may help elucidate the still elusive structural mechanisms of activation and inhibition of calcineurin. Our work illustrates the power of phenotypic screening of combinatorial protein libraries to interrogate the proteome and chart molecular regulatory networks.
de Chassey
Benoît
B
Aptanomics S.A., 181-203, avenue Jean Jaurès, 69007 Lyon, France.
Mikaelian
Ivan
I
Mathieu
Anne-Laure
AL
Bickle
Marc
M
Olivier
Delphine
D
Nègre
Didier
D
Cosset
François-Loïc
FL
Rudkin
Brian B
BB
Colas
Pierre
P
D000818:Animals; D052158:Aptamers, Peptide / Q000235:genetics / Q000494:pharmacology*; D019703:Calcineurin / Q000096:biosynthesis*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D005822:Genetic Vectors; D006801:Humans; D019151:Peptide Library; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D051381:Rats; D015302:Simian Immunodeficiency Virus / Q000235:genetics; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation
D052158:Aptamers, Peptide; D019151:Peptide Library; D019703:Calcineurin; D010744:Phosphoric Monoester Hydrolases