This document discusses chemically induced dimerization (CID), where two proteins bind only in the presence of a small molecule or other agent. It provides the history of CID, noting the first system used FK-1012 to induce homo-dimerization of FKBP. The mechanism involves two proteins that do not interact binding when a dimerizing agent is present. Applications include regulating gene transcription, signal transduction, and post-translational modification to control protein localization and manipulate signaling pathways. Examples given are FK-506/immunophilin and cyclosporine A/cyclophilin interactions.

1. CHEMICALLY INDUCED
DIMERIZATION (FK-
506/cyclosporin A)
Sir. Stymass Kasty
SOKOINE UNIVERSITY OF AGRICULTURE
MOROGORO-TANZANIA
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2. INTRODUCTION
Meaning
 Chemically Induced Dimerization (CID).;Refer to a
biological mechanism in which two proteins binds only in
the presence of a certain small molecule, enzyme or any
other dimerizing agent.
History
 First small molecule CID system was developed in 1993
and used FK-1012, a derivative of the drug Tacrolimus(FK-
506), to induce homo-dimerization of FK506-binding protein
(FKBP) in vivo.
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3. MECHANISM
Two proteins which do not interact, binds
in the presence of Dimerizing agent.
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4. MECHANISM
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5. APPLICATIONS
 The genetically engineered CID systems has been used to regulate
and monitor :-
• Gene transcription.
• Signal transduction.
• Post translational modification in proteins.
All in all to control protein localization, to manipulate signalling pathways
and induce protein activation.
 Cyclosporine A and Tacrolimus are used in the immunosuppression process after organ transplant to
inhibit graft rejection i.e. to induce interaction between proteins of interest from different origin.
 It have been also Used to create a basic component of bio-computers, logic gates from genetically
manipulated cells i.e. Cell ruffling (Two CID system, Plant protein and Bacterial protein expressed in the
same cell).
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6. EXAMPLES
 FK-506 - which interacts with immunophilin.
 Cyclosporine A - which interacts with cyclophilin.
 GAL4 (DNA binding protein)- which binds to the
promoter without activating transcription, and HSV
vp16 (activator) which can not bind to promoter;
when they interact, the combination of the two cause
activation of transgenic expression.
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7. Email. Stymass1@gmail.com
Contact.+255755527871
THANK YOU…!
!.<YOUR WELCOME>.!
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