<P> Functions of actin in the nucleus are associated with its ability to polymerization, interaction with variety of ABPs and with structural elements of the nucleus . Nuclear actin is involved in: </P> <Ul> <Li> Architecture of the nucleus - interaction of actin with alpha II - spectrin and other proteins are important for maintaining proper shape of the nucleus There is a dynamic connection between actin and the cell nucleus via KASH domain protein nesprins present the nuclear envelope and disruption of this connection leads to a change in nuclear morphology . </Li> <Li> Transcription--actin is involved in chromatin reorganization . transcription initiation and interacts with transcription complex . Actin takes part in the regulation of chromatin structure interact with both the RNA polymerase I, II and III In Pol I transcription, actin and myosin (MYO1C, which binds DNA) act as a molecular motor . For Pol II transcription, β - actin is needed for the formation of the preinitiation complex . Pol III contains β - actin as a subunit . Actin can also be a component of chromatin remodelling complexes as well as pre-mRNP particles (that is, precursor messenger RNA bundled in proteins), and is involved in nuclear export of RNAs and proteins . </Li> <Li> Regulation of gene activity--actin binds to the regulatory regions of different kinds of genes Actin ability to regulate gene activity is used in the molecular reprogramming method, which allows differentiated cells return to their embryonic state </Li> <Li> Translocation of the activated chromosome fragment from under membrane region to euchromatin where transcription starts . The movement require the interaction of actin and myosin </Li> <Li> Integration of different cellular compartments . Actin is a molecule that integrates cytoplasmic and nuclear signal transduction pathway . An example is the activation of transcription in response to serum stimulation of cells in vitro . </Li> </Ul> <Li> Architecture of the nucleus - interaction of actin with alpha II - spectrin and other proteins are important for maintaining proper shape of the nucleus There is a dynamic connection between actin and the cell nucleus via KASH domain protein nesprins present the nuclear envelope and disruption of this connection leads to a change in nuclear morphology . </Li> <Li> Transcription--actin is involved in chromatin reorganization . transcription initiation and interacts with transcription complex . Actin takes part in the regulation of chromatin structure interact with both the RNA polymerase I, II and III In Pol I transcription, actin and myosin (MYO1C, which binds DNA) act as a molecular motor . For Pol II transcription, β - actin is needed for the formation of the preinitiation complex . Pol III contains β - actin as a subunit . Actin can also be a component of chromatin remodelling complexes as well as pre-mRNP particles (that is, precursor messenger RNA bundled in proteins), and is involved in nuclear export of RNAs and proteins . </Li>

What is the function of the actin filament