Martha S. Briggs

Molecular Mechanisms of Protein Secretion: The Role of the Signal Sequence

Publisher Summary All cells make proteins that are destined for non-cytoplasmic locations, such as the extracellular fluid, the lumina of organelles, or the cell membranes. These proteins are almost invariably synthesized in the cytoplasm. Thus, such a protein must cross or enter one or more membranes in order to reach its destination. Furthermore, this process is specific in a manner that a particular protein travels only to its proper location, and only proteins destined for a particular location are transported there. The molecular mechanism of these processes has been the subject of intense investigation in the last decade. Most knowledge concerning the secretory process has come from genetic and biochemical studies. More recently, however, biophysical techniques have been used to investigate properties of the secretory apparatus and the signal sequence. The aim of this chapter is to describe the requirement for protein secretion and also to evaluate hypotheses of the ways in which secretion occurs. Particular emphasis is given to the role of the signal sequence.