OSBPL3 Q9H4L5

氧固醇结合蛋白相关蛋白 3 (ORP-3) (OSBP相关蛋白 3) (磷酸肌醇转移蛋白)

功能描述

脂质转运蛋白，在质膜(PM)/内质网(ER)接触位点介导磷酸肌醇4-磷酸(1,2-二酰基-sn-甘油-3-磷酸-(1D-肌醇4-磷酸), 或 PI(4)P)的非囊泡转运 (PubMed:16143324, PubMed:32041906, PubMed:32234213)。从质膜提取 PI4P，以交换磷脂酰胆碱 (PubMed:32234213)。能结合内质网膜蛋白 VAPA 并将 VAPA 募集到质膜位点，从而连接这些细胞内区室 (PubMed:25447204)。ORP3-VAPA 复合物刺激 RRAS 信号传导，进而减弱细胞表面整合素 beta-1 (ITGB1) 的活化 (PubMed:18270267, PubMed:25447204)。与 VAPA 一起，可能调节内质网形态 (PubMed:16143324)。在肌动蛋白细胞骨架、细胞极性和细胞粘附的调节中发挥作用 (PubMed:18270267)。结合磷酸肌醇，优先选择 PI(3,4)P2 和 PI(3,4,5)P3 (PubMed:16143324)。也结合 25-羟基胆固醇和胆固醇 (PubMed:17428193)。 {ECO:0000269|PubMed:16143324, ECO:0000269|PubMed:17428193, ECO:0000269|PubMed:18270267, ECO:0000269|PubMed:25447204, ECO:0000269|PubMed:32041906, ECO:0000269|PubMed:32234213}。

组织特异性

Expressed in a subset of small lymphocytes (at protein level). Expressed at high concentration in kidney, lymph node and thymus. Expressed at moderate concentration in stomach, jejunum, ileum, appendix, spleen, leukocytes, trachea, lung and thyroid gland. Expressed at low concentration in whole brain, esophagus, duodenum, ileocecum, colon, skeletal muscle, bone marrow, placenta and mammary gland (PubMed:14593528). Isoform 1a, isoform 1b, isoform 1c and isoform 1d are highly expressed in brain, bone marrow, colon, kidney, lung, skeletal muscle, spleen, thymus and thyroid. Not expressed in heart and liver. Isoform 2a, isoform 2b, isoform 2c and isoform 2d are expressed in brain, bone marrow, kidney, skeletal muscle, spleen, thymus and thyroid. Not expressed in heart, liver and lung (PubMed:12590732).

亚细胞定位

Endoplasmic reticulum membrane