Taxonomic distribution of proteins containing Longin domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing Longin domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Identification of the yeast R-SNARE Nyv1p as a novel longin domain-containingprotein.

Wen W, Chen L, Wu H, Sun X, Zhang M, Banfield DK
Mol Biol Cell. 2006; 17: 4282-99

Using nuclear magnetic resonance spectroscopy, we establish that the N-terminaldomain of the yeast vacuolar R-SNARE Nyv1p adopts a longin-like fold similar tothose of Sec22b and Ykt6p. Nyv1p is sorted to the limiting membrane of thevacuole via the adaptor protein (AP)3 adaptin pathway, and we show that itslongin domain is sufficient to direct transport to this location. In contrast, wefound that the longin domains of Sec22p and Ykt6p were not sufficient to directtheir localization. A YXX phi-like adaptin-dependent sorting signal (Y31GTI34)unique to the longin domain of Nyv1p mediates interactions with the AP3 complexin vivo and in vitro. We show that amino acid substitutions to Y31GTI34(Y31Q;I34Q) resulted in mislocalization of Nyv1p as well as reduced binding ofthe mutant protein to the AP3 complex. Although the sorting of Nyv1p to thelimiting membrane of the vacuole is dependent upon the Y31GTI34 motif, and Y31 inparticular, our findings with structure-based amino acid substitutions in the mu chain (Apm3p) of yeast AP3 suggest a mechanistically distinct role for thissubunit in the recognition of YXX phi-like sorting signals.