Mucin granule

Perez-Vilar J., Randell S.H. and Boucher R.C. (2004). C-Mannosylation of MUC5AC and MUC5B Cys subdomains. Glycobiology 4, 325-337 Perez-Vilar J., Olsen J.C., Chua M. and Boucher R.C. (2005a). pH-dependent intraluminal organization of mucin granules in live human mucous/goblet cells. J. Biol. Chem. 280, 16868-16881... 

Perez-Vilar J., Ribeiro C.M., Salmon W.C., Mabolo R. and Boucher R.C. (2005b). Mucin granules are in close contact with tubular elements of the endoplasmic reticulum. J Histochem Cytochem. 53, 1305-1309... 

Perez-Vilar J., Mabolo R. McVaugh C.T., Bertozzi C.R. and Boucher R.C. (2006). Mucin granule intraluminal organization in living mucous/goblet cells. Roles of protein post-translational modifications and secretion. J Biol Chem. 281, 4844-4855 Perez-Vilar J. (2007). Mucin granule intraluminal organization. Am J Respir Cell Mol Biol,... 

Perez-Vilar J. (2008) Formation of Mucin Granules. In The Golgi Apparatus. State of the Art 110 years After Camilo Golgi s Discovery (Mironov A. Pavelka M., eds.) Springer-Verlag, Viena/New York, pp. 535-562. 

The morphologic changes observed in cultures of embryonic chick skin exposed to all-/ranj-retinoic acid (tretinoin, Dl) were reversible and both dose- and time-dependent. Keratinization was inhibited and fewer desmosomes and tono-filaments were seen. Golgi elements, rough endoplasmic reticulum, and polyribosomes were unusually prominent. Mucin granules formed and gland-like structures developed with intercellular canaliculi characterized by tight junctions, brush borders, and dense secretory contents (Peck et al., 1977). 

Another illuminating implication of the proposed tangled network model was that it explained an old riddle, namely how could mucin networks, which are normally released from the granules in small discrete packages, interpenetrate each other, annealing into a continuum gel mass While the annealing property of mucus remained unexplained by the notion of an interchain S S bonded matrix, it was readily explained by the idea of a tangled mucin polymer network. 

A direct implication of this hypothesis is that phase transition of the mucus gel should be reversible, and it should exhibit the characteristic features of a critical phenomenon. Studies conducted in isolated giant mucin secretory granules of the terrestrial slug revealed that hydrated mucin gels, released from individual secretory granules, can indeed be recondensed. Recondensation/ decondensation is reversible and exhibits the typical features of a polymer gel phase transition. Namely, it is discontinuous, and is affected by pH, temperature and Ca2 + concentration in a fashion that mimics phase transition in synthetic polymer hydrogels [32, 33] (see Fig. 3). 

Fig. 3. Polymer gel phase transition of the mucin polymer matrix of a giant secretory granule of the terrestrial slug Ariolimax columbianus. Effect of pH...

---