| Popis: |
Striatin is a highly conserved eukaryotic protein first discovered in neuron cells of mammals. It is involved in many molecular processes, including cellular signaling, cell division and development. It has been shown in several fungi that striating complexes are important for development. Fungal development and secondary metabolism (SM) requires regulatory complexes which are under control of the environmental signals such as light, CO2 and pH . Aspergillus nidulans is a model for eukaryotic systems as well as fungal development and SM. It produces more than forty identified compounds with potent biological activities. Function of the striatin gene, strA was previously shown to influence development in A. nidulans. However, detailed molecular function of StrA in fungal development as well as SM production is still unknown. This study focuses on the interactome of striatin protein by using tandem affinity purification (TAP) and green fluorescent protein (GFP) tags in A. nidulans. Five proteins interacting or associated with StrA protein were identified TAP and GFP-TRAP by using mass spectrometry (MS). They were named as StrA interacting proteins (Sips), SipA, SipB, SipC, SipD and SipE. The single and double deletion combinations of all sipA, sipB, sipC, sipD and sipE genes led to serious developmental as well as SM defects in A. nidulans. Localization and pull-down experiments suggest that StrA is required for the full assembly of the functional STRIPAK complex at the nuclear envelope. Furthermore, assembly dynamics of the STRIPAK complex was also determined. StrA interacts with SipA constantly during all developmental stages. However, SipB-SipD and SipC-SipE are found as heterodimers, which later assemble to StrA-SipA core heterodimer, which constitute the hexameric STRIPAK complex. This study determines the presence of STRIPAK complex by biochemical, genetic and cell biological methods, which is required for light responses, fungal fruit body formation, asexual conidiation and secondary metabolite SM production. |
