Membrane-tethered mucins have multiple functions on the ocular surface.
Membrane-tethered mucins are large glycoproteins present in the glycocalyx along the apical surface of all wet-surfaced epithelia of the body, including that of the ocular surface. Originally thought to function only in epithelial surface lubrication and hydration, data now indicate that the mucins are multifunctional molecules, each having unique as well as common functions. This review summarizes current knowledge regarding the three major membrane mucins of the ocular surface, MUC1, MUC4, and MUC16. The mucins vary in their ocular surface distribution, size, structural motifs, and functions. The ectodomains of each are released into the tear film and are, thus, a component of the soluble mucins of the tear film. Both animal and in vitro models for their study are herein described, as are alterations of the mucins in ocular surface disease.
Govindarajan
Bharathi
B
Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
Gipson
Ilene K
IK
D000818:Animals; D018394:CA-125 Antigen / Q000502:physiology*; D003228:Conjunctiva / Q000378:metabolism*; D003229:Conjunctival Diseases / Q000378:metabolism; D003316:Corneal Diseases / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D019573:Epithelium, Corneal / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D018396:Mucin-1 / Q000502:physiology*; D055264:Mucin-4 / Q000502:physiology*
D018394:CA-125 Antigen; C060192:MUC1 protein, human; C451759:MUC16 protein, human; C524658:MUC4 protein, human; D008565:Membrane Proteins; D018396:Mucin-1; D055264:Mucin-4