High impact information on OSBPL3

• ORP-3, a human oxysterol-binding protein gene differentially expressed in hematopoietic cells [1].
• Characterization and differential expression of ORP-3 implicates a possible role in the mediation of oxysterol effects on hematopoiesis [1].
• Targeting of OSBP-related protein 3 (ORP3) to endoplasmic reticulum and plasma membrane is controlled by multiple determinants [2].
• A functional PH domain and flanking sequences are crucial for the plasma membrane (PM) targeting of ORP3 [2].
• Notably, over-expression of ORP3 together with VAP-A induces stacked ER membrane structures also known as organized smooth ER (OSER) [2].

Biological context of OSBPL3

• ORP6 gene expression was induced upon differentiation of F9 embryonic carcinoma cells into parietal endoderm, while ORP3 and ORP7 mRNA levels were unchanged [3].

Anatomical context of OSBPL3

• While ORP3 mRNA is most abundant in kidney, lymph nodes, and thymus, ORP6 shows highest expression in brain and skeletal muscle, and ORP7 in the gastrointestinal tract [3].
• The endoplasmic reticulum (ER) targeting of ORP3 is regulated the by a FFAT motif (EFFDAxE), which mediates interaction with VAMP-associated protein (VAP)-A [2].
• In addition, the exon 10/11 region modulates interaction of ORP3 with the ER and the nuclear membrane [2].

Associations of OSBPL3 with chemical compounds

• The pleckstrin homology (PH) domain of ORP3 binds the phosphoinositide-3-kinase (PI3K) products, PI(3,4)P2 and PI(3,4,5)P3 [2].
• Overexpression of ORP3 leads to formation of polarized cell-surface protrusions, impaired cell spreading and decreased beta1 integrin activity [4].

Regulatory relationships of OSBPL3

• Analysis of a chimeric ORP3:OSBP protein suggests that ligand binding by the C-terminal domain of OSBP induces allosteric changes that activate the N-terminal targeting modules of ORP3 [2].

Other interactions of OSBPL3

• The ORP-1 and -2 mRNA expression levels were similar to or higher than that of OSBP while the ORP-3 to -6 mRNAs were detected at lower levels in specific tissues [5].
• Here we performed basic characterization of subfamily III, which consists of three members: ORP3, ORP6, and ORP7 [3].

Analytical, diagnostic and therapeutic context of OSBPL3

• To further characterize the gene, we cloned ORP3 cDNA from PCR products and identified multiple splice variants [6].

References