Abstract
Proteins mediate nearly all the biological processes in cells. A protein molecule is a linear chain of 20 different amino acids, the sequence of which is specified by its gene. The life of a protein in the cell starts from its synthesis in the ribosome. The protein then undergoes many events and processes leading to its maturation, which include transport to the site of its function and folding and assembly into a unique structure that determines its function. Since the functional state of the protein is always under surveillance, it will be cured when it becomes defective. If it cannot be fixed any more or when it reaches the time for termination, the protein ends its life by degradation into amino acids. This lecture introduces the recent knowledge on the molecular basis of the sophisticated cellular systems that mediate those processes and biological consequences of their system failure, which may often lead to human diseases.
