Characterization of nPIST Mediated Actin Cytoskeleton Regulation

Das, Swagata (2014) Characterization of nPIST Mediated Actin Cytoskeleton Regulation. Masters thesis, Indian Institute of Science Education and Research Kolkata.

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Abstract

nPIST was previously reported to interact with Glutamate δ2 Receptor through its PDZ domain in cerebellar Purkinje cell. Its F-actin binding activity is a novel finding. It can bind to F-actin through its multiple actin binding sites namely coiled-coil 1 region, coiled-coil 2 region and PDZ domain. Multiple actin binding sites allows it to polymerize actin in vitro. Its coiled-coil domain has in vitro actin polymerization activity but the rate of polymerization is less than that of full length nPIST. However PDZ domain does not have any actin polymerization activity. On the other hand, coiled-coil sub-domain regions coiled-coil 1 and coiled-coil 2 has very negligible actin polymerization activity compared to coiled-coil domain. So, both these coiled-coil 1 and coiled-coil 2 regions bind to actin monomers simultaneously for actin nucleus formation and PDZ domain binds to another actin monomer and helps in actin polymerization. In vivo, over expressed full length nPIST and its coiled-coil domain cause unusual accumulation of actin which co-localizes with highly expressed full length nPIST and coiled-coil domain at peri-nuclear region. However, PDZ domain has localization all over the cell and has very small level of actin co-localization. As nPIST is a neuronal protein, there is possibility that nPIST may have a role in neuronal actin cytoskeleton regulation and synapse formation. Also, further biochemical analysis is required to find out the amino acids involved in actin binding.

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