ABSTRACT
In the last decade tremendous progress has been achieved in understanding the control of apoptosis by the cytokine/growth factor network of organisms as well as the molecular mechanisms of signal-transduction in preparation and final execution of the cells suicide. Accumulating evidence suggests that apoptosis is not the only type of programmed cell death (PCD) but that cells use different pathways for active self-destruction as reflected by different morphologies: While in apoptosis (or “type I”) condensation events are predominant, autophagy is a prominent characteristic of a second type of PCD (“type II”). Autophagic PCD appears to be a phylogenetically old phenomenon, it may occur in various organisms including hu mans in physiological and disease states. Recently, distinct biochemical and molecular features have been assigned to this type of PCD. However, autophagic and apoptotic PCD do not appear as mutually exclusive phenomena. Rather, they may occur simlutaneously in tissues or a cell may even switch from apoptotic to autophagic degradation of cytoplasmic structures. This chapter reviews morphological, functional and biochemical/molecular data on the role of the autophagosomal and lysosomal compartments in programmed cell death.
