ALK/LTK Subfamily  (间变性淋巴瘤激酶/白细胞酪氨酸激酶)

间变性淋巴瘤激酶 (ALK) 和白细胞酪氨酸激酶 (LTK) 受体属于受体酪氨酸激酶 (RTKs)，胰岛素受体 (IR) 超家族。它们具有独特的结构特征，包括高度保守的酪氨酸激酶结构域和配体结合的细胞外结构域中罕见的富含甘氨酸的区域，两个受体间这些区域显示 55% 的氨基酸相同。直到近年，ALK 和 LTK 的生理激活配体 FAM150A (ALKAL1/AUGβ) 和 FAM150B (ALKAL2/AUGα) 被鉴定出来后，ALK 和 LTK 去除了孤儿受体的称号。FAM150A 是 LTK 的高亲和性配体。FAM150B 是 ALK 和 LTK 的激活配体。ALK 和 LTK 具有潜在的致瘤特性。

Anaplastic Lymphoma Kinase (ALK) and Leukocyte Tyrosine Kinase (LTK) receptors are grouped within the insulin receptor (IR) superfamily of receptor tyrosine kinases (RTKs). They share distinctive structural features, including highly conserved tyrosine kinase domains and unusual glycine-rich regions in their ligand-binding extracellular domains (ectodomains) that exhibit 55% amino acid identity between the receptors. Until recently, ALK and LTK were deorphanized when their physiological activating ligands, FAM150A (ALKAL1/AUGβ) and FAM150B (ALKAL2/AUGα), were identified. FAM150A functions as a high-affinity ligand of LTK. FAM150B functions as an activating ligand of both ALK and LTK. ALK and LTK have potential oncogenic properties.