10q24.31. View the map and BAC contig (data from UCSC genome browser).
Isoform a/NM_173809: 5 exons, 12,728bp, chr12:54,396,087-54,399,751.
Isoform b/NM_001001342: 4 exons, 12, 402bp, chr10:101698300-101710701.
Alternative splicing of 5' exons causes the two different isoforms. Isoform b lacks the N-terminal 43aa of isoform a.
The figure below shows the structures of the BLOC1S2 genes (data from UCSC genome browser).
Search the 5'UTR and 1kb upstream regions (seq1=human BLOC1S2, seq2=mouse Bloc1s2) by CONREAL with 80% Position Weight Matrices (PWMs) threshold (view results here).
Tissue specificity: Ubiquitously expressed (by similarity)
BMR: Bone marrow; SPL: Spleen; TMS: Thymus; BRN: Brain; SPC: Spinal cord; HRT: Heart; MSL: Skeletal muscle; LVR; Liver; PNC: Pancreas; PST: Prostate; KDN: Kidney; LNG: Lung. (data from GeneCards )
|Protein||XP_193940 (143aa)||XP_215245 (142aa)||NP_648427 (159aa)||XP_315366 (141aa)||NP_500967 (132aa)|
View multiple sequence alignment (PDF file) by ClustalW and GeneDoc.
(1) Domains of predicted by SMART:
a) low complexity: 17 - 36
b) coiled coil: 111-127
(2) Transmembrane domains predicted by SOSUI: none.
(3) CDD domain: KOG4559.
(1) Predicted results by ScanProsite:
a) N-myristoylation site : [occurs frequently]
7 - 12: GVlaTR.
b) Casein kinase II phosphorylation site : [occurs frequently]
11 - 14: TrsD, 25 - 28: TaeE, 59 - 62: TseD.
c) Protein kinase C phosphorylation site : [occurs frequently]
74 - 76: SlK, 129 - 131: SkK.
d) N-glycosylation site : [occurs frequently]
86 - 89: NISR.
e) Leucine zipper pattern : [occurs frequently]
118 - 139: LeqaaykLdayskkLeakykkL.
f) Tyrosine kinase phosphorylation site : [occurs frequently]
130 - 136: Kkl.Eak.Y
g) Tyrosine sulfation site : [occurs frequently]
56 - 70: ltatsedYkllenmn.
(2) Predicted results of subprograms by PSORT II:
a) N-terminal signal peptide: none
b) KDEL ER retention motif in the C-terminus: none
c) ER membrane retention signals: KKXX-like motif in the C-terminus: KLEK
d) VAC possible vacuolar targeting motif: none
e) Actinin-type actin-binding motif: type 1: none; type 2: none
f) Prenylation motif: none
g) memYQRL transport motif from cell surface to Golgi: none
h) Tyrosines in the tail: none
i) Dileucine motif in the tail: none
j) DNA binding motif: Leucine zipper pattern (PS00029): found at 118.
(1) ModBase: none.
(2) 3D models of isoform (a) predicted by SPARKS (fold recognition) below. View the models by PDB2MGIF.
This protein does not exist in the current release of SWISS-2DPAGE.
Computed theoretical MW=15,961Da, pI=4.78 (isoform a).
Computed theoretical MW=11,489Da, pI=8.69 (isoform b).
(1) May play a role in intracellular vesicle trafficking.
(2) Protein interaction in BLOC-1.
Cytoplasmic. BLOS2 also localizes to centrosomes or the pericentrosomal region, and perhaps mitochondia.
BLOC-1 subunit 2 is a subunit of the biogenesis of lysosome-related organelles complex 1 (BLOC-1), where it resides with the products of seven other HPS genes, DTNBP1, MU, PLDN, CNO, BLOS1, BLOS3, SNAPAP (Ciciotte, et al; Falcon-Perez , et al; Li, et al; Moriyama, et al; Starcevic, et al). BLOS2 interacts with cno, muted, snapin, BLOS1, and BLOS3 within the complex ( Starcevic, et al) (view diagram of BLOC-1 complex here). In addition to BLOS2, WASH also interacts with centrosomal gamma-tubulin and with pallidin, suggesting WASH may be an additional component of the BLOC-1 complex ( Monfregola, et al).
Two alternatively human spliced isoforms of BLOS2, which are named as Ceap-11 (isoform b) and Ceap-16 (isoform a), are co-immunoprecipitated and colocalized with gamma-tubulin (Wang, et al). Ceap-16 interacts with BRD7 (bromodomain containing protein 7), a negative regulator of cell proliferation and growth. The C-terminus of BRD7 and the central region of Ceap-16 mediated the interaction. Ceap-16 may translocate from cytoplasm to the nucleus where it selectively inhibited the transcriptional suppression activity of BRD7. Furthermore, Ceap-16, BRD7 and histone H3/H4 could form a complex and Ceap-16 did not compete with the BRD7 binding to histones, suggesting a novel function for Ceap-16 in the transcriptional regulation through BRD7 (Sun, et al). AATF/Che-1 is a coactivator of several transcription factors, including steroid hormone receptors. BLOS2 was identified as an AATF interacting protein from a rat cDNA library. BLOS2 is conserved with a high degree of homology to yeast She3p. BLOS2 functions as an adapter in processes such as protein and vesicle processing and transport, and perhaps transcription (Felten, et al). In yeast two-hybrid screen, BLOS2 was identified as a novel HIPPI (HIP-1 protein interactor) interacting protein. In co-immunoprecipitation assays, BLOS2 specifically associates with HIPPI, but not with HIP-1 (Huntingtin-interacting protein-1), suggesting that BLOS2 might play an important functional role in cancer and neurodegenerative diseases (Gdynia, et al). In Arabidopsis, BLOS2 interacts with SNX1 to modulate the vacuole degradation of auxin effluxers PIN1/2 to regulate root development ( Cui, et al).
BLOS2 drosophila homolog CG14145 interaction information in CuraGen interaction database.
Involved in the development of lysosome-related organelles, such as melanosomes and platelet-dense granules (view diagram of BLOC-1 pathway here).