High impact information on BTN2

• BTN2 gene expression in the yeast Saccharomyces cerevisiae is up-regulated in response to the deletion of BTN1, which encodes the ortholog of a human Batten disease protein [1].
• We isolated Btn2 as a Snc1 v-SNARE binding protein using the two-hybrid assay and examined its role in intracellular protein trafficking [1].
• Btn2, a hook1 ortholog and potential batten disease-related protein, mediates late endosome-Golgi protein sorting in yeast [1].
• Thus, Btn2 facilitates specific protein retrieval from a late endosome to the Golgi apparatus, a process which may be adversely affected in patients with Batten disease [1].
• BTN2 encodes Btn2p, a proposed homologue to a novel microtubule-binding protein Hook1, which regulates endocytosis in Drosophila [2].

Biological context of BTN2

• The yeast model for batten disease: mutations in BTN1, BTN2, and HSP30 alter pH homeostasis [3].
• Up-regulation of BTN2 expression in btn1delta strains may facilitate either a direct or indirect effect on intracellular arginine levels [4].

Anatomical context of BTN2

• Btn2p was localized to the cytosol, suggesting a role in mediating pH homeostasis between the vacuole and plasma membrane H(+)-ATPase [3].
• We now report the biochemical and physical interactions of Btn2p with Ist2p, a plasma membrane protein that is thought to have a function in salt tolerance [5].

Associations of BTN2 with chemical compounds

• Deletion of BTN1, BTN2, or HSP30 does not alter cytosolic pH but diminishes pH buffering capacity and causes poor growth at low pH in a medium containing sorbic acid, a condition known to result in disturbed intracellular pH homeostasis [3].
• Overexpression of BTN2 results in a decreased rate of arginine uptake [4].
• We now report that Btn2p interacts biochemically and functionally with Rsglp, a down-regulator of the Can1p arginine and lysine permease [4].
• Rsglp localizes to a distinct structure toward the cell periphery, and strains lacking Btn2p (btn2delta strains) fail to correctly localize Rsg1p. btn2delta strains, like rsg1delta strains, are sensitive for growth in the presence of the arginine analog canavanine [4].
• Btn2p, a novel coiled-coil protein, is up-regulated in btn1delta yeast strains, and this up-regulation is thought to contribute to maintaining a stable vacuolar pH in btn1delta strains (D. A. Pearce, T. Ferea, S. A. Nosel, B. Das, and F. Sherman, Nat. Genet. 22:55-58, 1999) [4].

Other interactions of BTN2

• This up-regulation of Btn2p was shown to contribute to the maintenance of a stable vacuolar pH in the btn1Delta strain [5].

References