phosphatidylserine binding

Definition

Target type: molecularfunction

Binding to phosphatidylserine, a class of glycophospholipids in which a phosphatidyl group is esterified to the hydroxyl group of L-serine. [ISBN:0198506732, PMID:12000961]

Phosphatidylserine (PS) binding is a crucial molecular function that involves the interaction of proteins with PS, a negatively charged phospholipid found predominantly in the inner leaflet of the plasma membrane. This interaction plays a critical role in various cellular processes, including signal transduction, membrane trafficking, and apoptosis.

PS binding proteins can be broadly classified into two categories:

**1. Translocators:** These proteins facilitate the movement of PS from the inner leaflet to the outer leaflet of the plasma membrane. This "flipping" of PS is essential for several functions, including:

* **Apoptosis:** During programmed cell death, PS is exposed on the outer leaflet of the cell membrane, acting as an "eat me" signal for phagocytes. This process ensures the efficient removal of apoptotic cells without causing inflammation.
* **Platelet activation:** PS exposure on platelet membranes during blood clotting triggers the binding of coagulation factors, initiating the formation of blood clots.

**2. Receptors and binding proteins:** These proteins directly interact with PS on the inner or outer leaflet of the membrane, mediating various signaling pathways and cellular processes.

**Specific examples of PS binding proteins include:**

* **Scramblases:** These membrane proteins facilitate the bidirectional movement of phospholipids across the membrane, including PS, leading to its exposure on the outer leaflet.
* **Flippase:** This protein transports PS from the outer leaflet to the inner leaflet of the membrane, maintaining its asymmetric distribution.
* **Annexins:** These proteins bind to PS with high affinity, particularly in the presence of calcium ions. Annexins are involved in various cellular processes, including membrane fusion, exocytosis, and inflammation.
* **C1q:** This protein, part of the complement system, binds to PS exposed on the surface of apoptotic cells, triggering the complement cascade.

**Overall, PS binding is a dynamic process that plays a vital role in maintaining cell membrane integrity, regulating cellular signaling, and mediating critical events such as apoptosis and coagulation. The specific function of PS binding proteins depends on their location, binding affinity, and interaction with other cellular components.**'
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Proteins (11)

Compounds (137)