Platelet Factor 4 Variant 1  (CXC 趋化因子配体 4 变体 1)

PF4V1，也称为 CXCL4L1，是 CXCL4 的非等位基因变体。PF4V1 是一种血小板相关趋化因子，它与肝素的结合比在密切同源物 PF4/CXCL4 中的结合要弱得多。PF4V1 是血管生成抑制剂和内皮细胞趋化性抑制剂。PF4V1 与炎症、血管生成和癌症有关。PF4V1 最初是从凝血酶刺激的血小板中分离出来的。全长人 CXCL4L1/PF-4var 由 104 个氨基酸组成。CXCL4L1 似乎由血小板、平滑肌细胞、人主动脉和冠状动脉平滑肌细胞组成型释放，并且可在单核细胞、内皮细胞和骨肉瘤细胞中被炎症介质诱导。CXCL4L1 在炎症、血管生成和癌症中发挥作用^[1][2][3]。
CXCL4 及其非等位基因变体 CXCL4L1 都是血小板衍生的趋化因子。成熟的 CXCL4L1 蛋白由 70 个氨基酸组成，仅在位于蛋白质羧基末端部分的三个氨基酸不同 (Pro58) Leu、Lys66) Glu、Leu67) His； CXCL4) CXCL4L1)。由于氨基酸的这些变化，CXCL4L1 被认为具有不同的二级结构和对肝素的较低亲和力。在体内，通过免疫组织化学在肉瘤组织中检测到 CXCL4L1 的弱到强表达。CXCL4L1 作为活化 T 细胞、NK 细胞和未成熟树突状细胞的趋化剂起作用。与 CXCL4 相比，CXCL4L1 是一种更有效的血管抑制趋化因子。与 CXCL4 相比，CXCL4L1 不太可能与 fFGF2 和 VEGF 形成异二聚体或竞争 GAG 结合^[1][2][3]。

PF4V1, also known as CXCL4L1, is a non-allelic variant of CXCL4. PF4V1 is a platelet-associated chemokine, and it binds to heparin is much weaker than in the close homolog PF4/CXCL4. PF4V1 is an inhibitor of angiogenesis and inhibitor of endothelial cell chemotaxis. PF4V1 is involved in inflammation, angiogenesis, and cancer. PF4V1 is originally isolated from thrombin stimulated platelets. Full-length human CXCL4L1/PF-4var is comprised of 104 amino acids. CXCL4L1 seems to be constitutively released by platelets, smooth muscle cells, human aortic and coronary smooth muscle cells and is inducible in monocytes, endothelial and osteosarcoma cells by inflammatory mediators. CXCL4L1 plays a role in inflammation, angiogenesis and cancer^[1][2][3].
CXCL4 and its non-allelic variant CXCL4L1 are both platelet-derived chemokines. The mature CXCL4L1 protein is composed of 70 amino acids and differs in only three amino acids situated in the carboxy-terminal part of the protein (Pro58 ) Leu, Lys66 ) Glu, Leu67 ) His; CXCL4 ) CXCL4L1). Due to these changes in amino acids, CXCL4L1 is supposed to have a different secondary structure and a lower affinity for heparin. In vivo, weak to strong expression of CXCL4L1 was detected in sarcoma tissue by immunohistochemistry. CXCL4L1 functions as a chemoattractant for activated T cells, NK cells and immature dendritic cells. CXCL4L1 is a more potent angiostatic chemokine compared to CXCL4. Compared to CXCL4, CXCL4L1 is less likely to form heterodimers with fFGF2 and VEGF or to compete for GAG-binding^[1][2][3].

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