Phosphatidylserine (PS) is an anionic phospholipid found on the membranes of a variety of organelles throughout the cell, most notably the plasma membrane. Under homeostatic conditions, PS is typically restricted to the inner leaflet of the plasma membrane. However, during cellular activation and/or induction of cell death, PS is externalized on the outer surface via the activation of phospholipid scramblases. Externalized PS not only changes the biochemical and biophysical properties of the plasma membrane but also initiates a series of interactions between endogenous extracellular proteins as well as receptors on neighboring cells to stimulate engulfment (efferocytosis) that influence the surrounding immune milieu. In this thematic series published in Cell Communication and Signaling, we feature review articles that highlight recent work in the field of PS biology, including the biochemistry and physiological significance of PS externalization, therapeutic applications and efforts to target PS, as well as posit open questions that remain in the field.

中文翻译：

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磷脂酰丝氨酸（PS）的生物学：基本生理学及其对免疫学，传染病和癌症的影响。

磷脂酰丝氨酸（PS）是一种阴离子磷脂，存在于整个细胞的各种细胞器的膜上，最明显的是质膜。在稳态条件下，PS通常局限于质膜的内部小叶。然而，在细胞活化和/或细胞死亡诱导期间，PS通过磷脂scramblases的活化在外表面外在化。外部化的PS不仅会改变质膜的生化和生物物理特性，而且还会引发内源性细胞外蛋白与邻近细胞上的受体之间的一系列相互作用，从而刺激吞噬（胞吞作用），从而影响周围的免疫环境。在《细胞通讯与信号》中发表的这一专题系列中，