Comparison of the Network Structure and the Pattern of Network Extension in Intracellular Organelles of Yeast

Abstract

Large-scale information-spreading processes, such as scale-free networks, mostly follow a smallworld principle. In contrast, the processing of information at a person-to-person level follows a narrow and deep tree-like pattern. This information-spreading style represents a type of local communication dynamic within a small-world social network. We constructed local protein-interaction networks for cytoplasm, mitochondria, nucleus, and endosomes, and then characterized their structural properties and patterns of extension. Although the mitochondrial protein network possessed a scale-free character, similar to the networks of other organelles, it had a relatively large diameter. It was difficult to identify possible narrow, deep-reaching style characteristics because of the small mitochondrial dataset. However, the network structure was clearly distinguishable from that of the other organelles. We characterized diameter extension processes and network evolution by randomly extending the number of nodes or edges, showing that the mitochondrial network extension process was relatively distinct from that of other organelle networks in diameter but not in evolution rate. The network structure and the pattern of extension of the protein-interaction network in mitochondria are distinct from those of the cytoplasm, nucleous, and endosome. These differences may be a reflection of the unique origin and distinct functions of mitochondria.