Three main types of autophagy have been described: (1) microautophagy,
in which lysosomes directly take up portions of cytoplasm
for degradation; (2) chaperone-mediated autophagy, in which
chaperone proteins recognise and transport cytoplasmic proteins
to the lysosome; and (3) macroautophagy, where there is nonselective
sequestration of cytoplasmic material for lysosomal
degradation. The latter process has been the focus of a large body
of research and represents the most important type of autophagy