Manipulation of Ca2+-dependent transcription factor activation and cell cycle progression by optogenetics

Abstract

Calcium ion (Ca2+) plays an one of the major second messengers in many physio-logical processes such as cell proliferation death muscle contraction gene regulation and cancer migration and invasion However control of intracellular Ca2+ with spatial and temporal precision is a limitation in the current studies on these topics Here we present an optogenetic method to manipulate Ca2+-dependent gene transcription using three tran-scription factors including NFAT (nuclear factor of activated T-cells) CREB (cAMP re-sponse element-binding protein) and NFκB (nuclear factor-κB) and the regulation of cell cycle progression in the transition of G1/S and G2/M The customized optogenetics plat-form was setup for the purpose of controlling stimulations in living cells U2OS cells overexpressing calcium translocating channelrhodopsin (CatCh) can be used to mediate Ca2+ influx by illumination with 470 nm blue light The profiles of a Ca2+ wave can be regulated by using various parameters of blue light illumination such as the power fre-quency duty cycle and duration By manipulating optogenetic induced Ca2+ influx a se-ries of the patterns of Ca2+ oscillation with different parameters of power can be generated The results show that optogenetic technology defines the spatial temporal and amplitude features of Ca2+ signals The finding indicates that NFAT activation requires large amounts of Ca2+ whereas NFκB only needs a small amount of Ca2+ On the other hand CREB can be activated with not only large amounts of Ca2+ but also with small amounts of Ca2+ In addition it is understood that Ca2+ participates in the G1/S transition of the cell cycle rather in the G2/M transition And the patterns of Ca2+ oscillation determine how the cell cycle progression is driven This study resolves dynamic components of Ca2+ os-cillation with regard to decoding Ca2+ signals and has the potential to development Ca2+ signalling related research

Date of Award	2016 Aug 1
Original language	English
Supervisor	Wen-Tai Chiu (Supervisor)