- ubiquitin-dependent protein catabolic process via the N-end rule pathway
The chemical reactions and pathways resulting in the breakdown of a protein or peptide covalently tagged with ubiquitin, via the N-end rule pathway. In the N-end rule pathway, destabilizing N-terminal residues (N-degrons) in substrates are recognized by E3 ligases (N-recognins), whereupon the substrates are linked to ubiquitin and then delivered to the proteasome for degradation.
- UBR1-RAD6 ubiquitin ligase complex
A ubiquitin ligase complex consisting of UBR1 and RAD6 components. It polyubiquitinates proteins containing non-acetylated N-terminal residues causing their subsequent degradation by the proteasome as part of the Ac/N-End Rule pathway. It recognizes non-acetylated N-terminal methionine if it is followed by a hydrophobic residue. Additionally, it acts in an N-end rule independent manner as a component of a novel quality control pathway for proteins synthesized on cytosolic ribosomes.
- RAD6-UBR2 ubiquitin ligase complex
A ubiquitin ligase complex consisting of RAD6 and UBR2 components. It may act in a quality control pathway for proteins synthesized on cytosolic ribosomes. The UBR2 component lacks sequence motifs required for N-end rule degradation.
- posterior head segmentation
Partitioning the posterior region of the insect head anlage into gnathal (mandibular, maxillary and labial) segments. Unlike the anterior head (procephalic) segments, formation of the posterior head (gnathal) segments occurs by a similar mechanism to trunk segmentation, where a cascade of gap genes, pair-rule genes and segment-polarity genes subdivide the embryo into progressively smaller domains.