Okigaki M, Davis C, Falasca M, Harroch S, Felsenfeld D P, Sheetz M P, Schlessinger J
Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
Proc Natl Acad Sci U S A. 2003 Sep 16;100(19):10740-5. doi: 10.1073/pnas.1834348100. Epub 2003 Sep 5.
The biological role of the protein tyrosine kinase, Pyk2, was explored by targeting the Pyk2 gene by homologous recombination. Pyk2-/- mice are viable and fertile, without overt impairment in development or behavior. However, the morphology and behavior of Pyk2-/- macrophages were impaired. Macrophages isolated from mutant mice failed to become polarized, to undergo membrane ruffling, and to migrate in response to chemokine stimulation. Moreover, the contractile activity in the lamellipodia of Pyk2-/- macrophages was impaired, as revealed by measuring the rearward movement toward the nucleus of fibronectin-coated beads on the lamellipodia in opposition to an immobilizing force generated by optical tweezers. Consistently, the infiltration of macrophages into a carageenan-induced inflammatory region was strongly inhibited in Pyk2-/- mice. In addition, chemokine stimulation of inositol (1, 4, 5) triphosphate production and Ca2+ release, as well as integrin-induced activation of Rho and phosphatidyl inositol 3 kinase, were compromised in Pyk2-/- macrophages. These experiments reveal a role for Pyk2 in cell signaling in macrophages essential for cell migration and function.
通过同源重组靶向Pyk2基因，探讨了蛋白酪氨酸激酶Pyk2的生物学作用。Pyk2基因敲除小鼠能够存活且可育，发育或行为未出现明显损伤。然而，Pyk2基因敲除巨噬细胞的形态和行为受到损害。从突变小鼠中分离出的巨噬细胞无法极化、形成膜皱褶，也无法对趋化因子刺激做出迁移反应。此外，通过测量纤连蛋白包被的珠子在片足上朝着细胞核的向后移动，以对抗光镊产生的固定力，结果显示Pyk2基因敲除巨噬细胞片足的收缩活性受损。一致地，Pyk2基因敲除小鼠中巨噬细胞向角叉菜胶诱导的炎症区域的浸润受到强烈抑制。此外，Pyk2基因敲除巨噬细胞中，趋化因子刺激引起的肌醇（1,4,5）三磷酸生成和Ca2+释放，以及整合素诱导的Rho和磷脂酰肌醇3激酶激活均受到损害。这些实验揭示了Pyk2在巨噬细胞的细胞信号传导中所起的作用，而这对于细胞迁移和功能至关重要。
