Mucin endoplasmic reticulum

Fig. 2.4 Biosynthesis of gel-forming mucins. Schematic representation of the major steps occurring during the biosynthesis of mucins. Mucin biosynthesis is a sequential process that starts in the endoplasmic reticulum and ends in the trans-compartments of the Golgi complex. Formation of disulfide-linked oligomers/multimers involves two steps dimerization in the endoplasmic reticulum and interdimeric disulfide bonding in the Golgi complex. O-Glycosy-lation of dimeric precursors results in more extended but still flexible chains. See text for further details. Rectangles indicate the NH-terminal D-domains while circles and the bars represent the COOH-terminal CK-domains and the O-glycan chains, respectively...

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... 

Hilkens J, Buijs F. Biosynthesis of MAM-6, an epithelial sialo-mucin. Evidence for involvement of a rare proteolytic cleavage step in the endoplasmic reticulum. J Biol Chem. 1988 263 4215-4222. 

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). 

Dekker, J., and Strous, G. J., 1990, Covalent oligomerization of rat gastric mucin occurs in the rough endoplasmic reticulum, is N-glycosylation dependent, and precedes initial O-glycosylation, J. Biol. Chem. 265 18116-18122. 

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