Weibel–Palade body
Weibel–Palade bodies (WPBs) are the
Etymology
Weibel–Palade bodies were initially described by the
Constituents
There are two major components stored within Weibel–Palade bodies. One is
Additional Weibel–Palade body components are the chemokines
Production
Multimeric vWF is assembled head-to-head in the Golgi apparatus from tail-to-tail vWF dimers. vWF multimers condense and twist into long, helical, mostly parallel tubules separated by a less dense matrix of protein domains protruding from the tubules.[9] The Golgi then buds off clathrin-coated vesicles which consist almost exclusively of vWF.
Immature Weibel–Palade bodies remain near the nucleus, where they acquire more membrane proteins and then disperse throughout the cytoplasm, carried along
The only parallel organelle in physiology is the alpha granule of platelets, which also contains vWF. Weibel–Palade bodies are the main source of vWF, while α-granules probably play a minor role.
Secretion
The small subset of Weibel–Palade bodies tethered at the cell periphery to the actin cortex serve as a readily releasable pool that's replenished by a larger pool of microtubule-associated bodies in the cell interior.[8]
The contents of Weibel–Palade bodies are secreted by one of three mechanisms.
During secretion, the vWF molecules fuse together into the final concatamer "strings".[10]
Clinical significance
The importance of Weibel–Palade bodies are highlighted by some human disease mutations. Mutations within vWF are the usual cause of the most common inherited bleeding disorder,
See also
References
External links
- Weibel-Palade Bodies at the U.S. National Library of Medicine Medical Subject Headings (MeSH)