Prostaglandins (PGs) are important mediators of bone response to growth factors, hormones, inflammation, or mechanical strains. In this study, we show that in MG63 osteosarcoma cells, prostaglandin E2 (PGE2) produces the opening of a large conductance Ca2+‐dependent K+ channel (BK). This PGE2‐mediated channel opening induces the recruitment of various tyrosine‐phosphorylated proteins on the hSlo α‐subunit of BK. Because the C‐terminal domain of hSlo encompasses an immunoreceptor tyrosine‐based activation motif (ITAM), we show that the Syk nonreceptor tyrosine kinase, reported yet to be expressed mainly in hematopoietic cells, is expressed also in osteoblastic cells, and recruited on this ITAM after a PGE2‐induced docking/activation process. We show that Syk/hSlo association is dependent of an upstream Src‐related tyrosine kinase activity, in accord with the classical two‐step model described for immune receptors. Finally, we provide evidence that this Syk/hSlo interaction does not affect the electrical features of BK channels in osteosarcoma cells. With these data, we would like to suggest the new notion that besides its conductance function, hSlo channel can behave in bone cells, as a true transduction protein intervening in the bone remodeling induced by PGE2.
                                    前列腺素(
PGs)是骨骼对生长因子、激素、炎症或机械应变做出反应的重要介质。在这项研究中,我们发现在 MG63 骨肉瘤细胞中,
前列腺素 E2(
PGE2)会导致大电导 Ca2+ 依赖性 K+ 通道(BK)开放。这种由 
PGE2 介导的通道开放会诱导 BK 的 hSlo α 亚基上各种
酪氨酸磷酸化蛋白的招募。由于 hSlo 的 C 端结构域包含一个基于免疫受体
酪氨酸的激活基序(ITAM),我们发现据报道主要在造血细胞中表达的 Syk 非受体
酪氨酸激酶也在成骨细胞中表达,并在 
PGE2 诱导的对接/激活过程后被招募到 ITAM 上。我们的研究表明,Syk/hSlo 的结合依赖于上游 Src 相关
酪氨酸激酶的活性,这与免疫受体的经典两步模型相符。最后,我们提供的证据表明,这种 Syk/hSlo 相互作用不会影响骨肉瘤细胞中 BK 通道的电特性。有了这些数据,我们想提出一个新的观点,即 hSlo 通道除了具有传导功能外,还能在骨细胞中作为真正的传导蛋白介入 
PGE2 诱导的骨重塑过程。