Platelet Factor 4 (PF4), is a member of the CXC chemokine family. Human PF4 is a 101 amino acid (aa) protein with a 32aa signal sequence and a 70aa mature protein. PF4 has homology with IL-8 and beta -thromboglobulin. Human and mouse PF4 share a 64% identity. PF4 contains several heparin-binding sites at the C-terminal region. The active protein consists of a tetramer composed of individual PF4 subunits. Megakaryocytes synthesize PF4 and store it as tetramers in alpha-granules. The PF4 tetramers are secreted by activated platelets and can be measured at micromolar levels in serum. In contrast to other CXC chemokines, PF4 lacks chemotactic activity for polymorphonuclear granulocytes. PF4 does not contain an ELR motif. However, many other functions have been observed for PF4. PF4 is involved in monocyte survival and differentiation into macrophages, and it has anti-angiogenic activity. PF4 has been demonstrated to inhibit the binding of FGF-2 to high-affinity receptors, contributing to its subsequent internalization. Cell surface neutrophil chondroitin sulfate chains serve as PF4 binding sites; affinity is controlled by the degree of sulfation of these chains.
Suitable for use in Flow Cytometry. Other applications not tested.
Flow Cytometry: 10ul labels 5x10e5 cells
Optimal dilutions to be determined by the researcher.
Storage and Stability:
May be stored at 4 degrees C before opening. DO NOT FREEZE! Stable at 4 degrees C. Stable for 12 months at 4 degrees C. Freezing R-Phycoerythrin (PE) conjugates will result in a substantial loss of activity. PE conjugates are sensitive to light.