Autophagy: molecular mechanisms, physiological functions and relevance in human pathology.

Autophagy is a degradative mechanism mainly involved in the recycling and turnover of cytoplasmic constituents from eukaryotic cells. Over the last years, yeast genetic screens have considerably increased our knowledge about the molecular mechanisms of autophagy, and a number of genes involved in fundamental steps of the autophagic pathway have been identified. Most of these autophagy genes are present in higher eukaryotes indicating that this process has been evolutionarily conserved. In yeast, autophagy is mainly involved in adaptation to starvation, but in multicellular organisms this route has emerged as a multifunctional pathway involved in a variety of additional processes such as programmed cell death, removal of damaged organelles and development of different tissue-specific functions. Furthermore, autophagy is associated with a growing number of pathological conditions, including cancer, myopathies and neurodegenerative disorders. The physiological and pathological roles of autophagy, as well as the molecular mechanisms underlying this multifunctional pathway, are discussed in this review.