This domain is found in bacteria, archaea and eukaryotes. This domain is typically between 320 to 354 amino acids in length. This domain is found associated with Pfam:PF04685. It is found just after the extreme N terminus. The N-terminal is thought to be the luminal domain while the C terminal is the cytosolic domain. The catalytic domain of GBA-2 is unknown. The primary catabolic pathway for glucosylceramide is catalysis by the lysosomal enzyme glucocerebrosidase. In higher eukaryotes, glucosylceramide is the precursor of glycosphingolipids, a complex group of ubiquitous membrane lipids [1]. Mutations in the human protein cause motor-neurone defects in hereditary spastic paraplegia [2,3]. The catalytic nucleophile, identified in UniProtKB:Q97YG8_SULSO, is a glutamine-335 in the downstream family Pfam:PF04685 [4].

1: Identification of the non-lysosomal glucosylceramidase as beta-glucosidase 2. Boot RG, Verhoek M, Donker-Koopman W, Strijland A, van Marle J, Overkleeft HS, Wennekes T, Aerts JM; J Biol Chem. 2007;282:1305-1312. PMID:17105727

2: Loss of function of glucocerebrosidase GBA2 is responsible for motor neuron defects in hereditary spastic paraplegia. Martin E, Schule R, Smets K, Rastetter A, Boukhris A, Loureiro JL, Gonzalez MA, Mundwiller E, Deconinck T, Wessner M, Jornea L, Oteyza AC, Durr A, Martin JJ, Schols L, Mhiri C, Lamari F, Zuchner S, De Jonghe P, Kabashi E, Brice A, Stevanin G; Am J Hum Genet. 2013;92:238-244. PMID:23332916

3: Mutations in GBA2 cause autosomal-recessive cerebellar ataxia with spasticity. Hammer MB, Eleuch-Fayache G, Schottlaender LV, Nehdi H, Gibbs JR, Arepalli SK, Chong SB, Hernandez DG, Sailer A, Liu G, Mistry PK, Cai H, Shrader G, Sassi C, Bouhlal Y, Houlden H, Hentati F, Amouri R, Singleton AB; Am J Hum Genet. 2013;92:245-251. PMID:23332917

4: A new archaeal beta-glycosidase from Sulfolobus solfataricus: seeding a novel retaining beta-glycan-specific glycoside hydrolase family along with the human non-lysosomal glucosylceramidase GBA2. Cobucci-Ponzano B, Aurilia V, Riccio G, Henrissat B, Coutinho PM, Strazzulli A, Padula A, Corsaro MM, Pieretti G, Pocsfalvi G, Fiume I, Cannio R, Rossi M, Moracci M; J Biol Chem. 2010;285:20691-20703. PMID:20427274