Two different kinds of sorting signals:

Membrane cargo proteins carry cytoplasmic sorting signals

Soluble cargo proteins carry luminal sorting signals

TLS Online TPP Program

#Id: 8223

#Section 3: Genetics, Cellular and Molecular Biology

Retromer

a coat protein complex specialized for endosome-to-TGN transport, recycle the M6P receptor to the TGN

TLS Online TPP Program

#Id: 8221

#Section 3: Genetics, Cellular and Molecular Biology

The M6P receptor protein binds to M6P at pH 6.5–6.7 in the TGN lumen and releases it at pH 6, in the lumen of endosomes.

TLS Online TPP Program

#Id: 8219

#Section 3: Genetics, Cellular and Molecular Biology

M6P residues are generated in the cis-Golgi by two Golgi-resident enzymes. 

1. N-acetylglucosamine (GlcNAc) phosphotransferase
2. Phosphodiesterase

TLS Online TPP Program

#Id: 8218

#Section 3: Genetics, Cellular and Molecular Biology

Sorting signal that directs lysosomal hydrolases from the TGN to the late endosome is- Mannose 6-phosphate (M6P).

TLS Online TPP Program

#Id: 8217

#Section 3: Genetics, Cellular and Molecular Biology

In selective autophagy

specific cargo is packaged into autophagosomes that tend to contain little cytosol, mediates the degradation of worn out, or unwanted, mitochondria, peroxisomes, ribosomes, and ER; used to destroy invading microbes.

TLS Online TPP Program

#Id: 8216

#Section 3: Genetics, Cellular and Molecular Biology

In nonselective autophagy, a bulk portion of cytoplasm is sequestered in autophagosomes