Protein translocation in mitochondria: Sorting out the Toms, Tims, Pams, Sams and Mia

Mitochondria contain 902 (yeast) to 1.136 (mouse, humans) verified proteins. Except for a very small number of mitochondrially encoded core components of the respiratory chain, mitochondrial proteins are encoded by nuclear genes and synthesized in the cytosol. Different import pathways direct proteins to their respective mitochondrial subcompartment (outer membrane, intermembrane space (IMS), inner membrane and matrix). Specific targeting signals in their sequence direct proteins to their target destination and allow the proteins to embark on their respective import pathway. The main import pathways are shown here on the poster and are introduced in the following, using the mitochondrial import system of the baker's yeast Saccharomyces cerevisiae as example. However, the mitochondrial import system of mammalian cells is highly similar and deviates only in minor aspects. Even the mitochondrial import machineries of less closely related eukaryotes, such as plants and trypanosomes, are very similar and adhere to the same general principles.

Fractures of the talus

The talus is the most proximal bone of the hindfoot that couples the foot to the leg. It is the second most common fracture of the tarsal bones, second in frequency to the calcaneous. However, overall injuries to the talus are relatively rare, and most surgeons have little experience in managing them. This article discusses fractures of the talus, including injuries to the talar neck, body, head, and processes. Although subtalar dislocations and osteochondral injuries are important topics, they are not addressed in this article.