(Alliance, FBgn0003942 )

Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-48-linked is involved in protein degradation via the proteasome. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling (By similarity). Ribosomal protein S27a is a component of the 40S subunit of the ribosome.

(UniProt, P15357)

Homozygotes have short thin bristles; relative viability 25% at 25; hemizygotes lethal. Both males and females sterile at 25 but some fertility observed in flies raised at 23. Males raised at 28.5 have no motile sperm and some spermatids have micronuclei, and occasionally two basal bodies and axonemes are observed.

Structural gene for ubiquitin (Lee et al., 1988). Ubi-m codes for a fusion protein whose single ubiquitin sequence is attached to a tail polypeptide with 65% identity to the yeast ubiquitin tail protein and 82% identity to the human ubiquitin tail protein. Ubiquitin-monomeric is not inducible by heat shock.