High impact information on TIP20

• The TIP1 gene of Saccharomyces cerevisiae encodes an 80 kDa cytoplasmic protein that interacts with the cytoplasmic domain of Sec20p [1].
• Dsl1p, Tip20p, and the novel Dsl3(Sec39) protein are required for the stability of the Q/t-SNARE complex at the endoplasmic reticulum in yeast [2].
• The Saccharomyces cerevisiae early secretion mutant tip20 is synthetic lethal with mutants in yeast coatomer and the SNARE proteins Sec22p and Ufe1p [3].
• Since carboxy-terminal tip20 truncations are lethal in combination with mutants in three coatomer subunits, Tip20p might be involved in binding or uncoating of COPI coated retrograde transport vesicles [3].
• Here we describe a novel temperature-sensitive allele of TIP20 and analyze its phenotype [4].

Biological context of TIP20

• These results demonstrate the occurrence and function of Sec20p in a fungal species other than S. cerevisiae, but the lack of the N-terminal domain and the apparent absence of a close TIP20 homolog in the C. albicans genome also indicate a considerable diversity in mechanisms of retrograde vesicle traffic in eukaryotes [5].

Anatomical context of TIP20

• However, a specific mutant of TIP20 did not interfere with COPII vesicle generation but allowed these vesicles to fuse back to the endoplasmic reticulum, a process that does not occur normally in the cell [6].

Associations of TIP20 with chemical compounds

• These results suggest a role for the Sec20/Tip20p complex in retrieval of dilysine-tagged proteins back to the ER [4].
• Three domains were identified in Dsl1p: a Tip20p binding region within the N-terminal 200 residues, a highly acidic region in the center of Dsl1p containing crucial tryptophan residues that is required for binding to delta-COP and essential for viability, and an evolutionarily well conserved domain at the C terminus [7].

Physical interactions of TIP20

• The Sec20/Tip20p complex is involved in ER retrieval of dilysine-tagged proteins [4].

Other interactions of TIP20

• The approximately 80-kDa protein has been identified as Tip20p, a protein that others have shown to exist in a tight complex with Sec20p, which is approximately 50 kDa [8].

References