Abstract
Thirteen members of aquaporin (AQP), a water channel, are expressed in mammals. In this review, we briefly overview these mammalian AQPs, then focus on AQP5, an exocrine gland-type AQP. Namely, we discuss: (1) the mechanism for coupling of AQP5 dynamics with the secretion and restoration cycle of amylase after isoproterenol (IPR) in the parotid gland (PG); (2) roles of parasympathetic nerve for maintaining AQP5 level in the submandibular gland (SMG), and; (3) AQP5 down-regulation in an experimental pathological model by LPS administration in the PG. We then move to the effects of single nucleotide mutation (SNP) found in rats and humans and its affected phenotypes. That is, G308A point mutation found in rat AQP5 cDNA resulted in amino acid substitutions of Gly103 for Asp103, and causes diminished expression of its protein product. In humans, several SNPs in AQP5 are found in European and Chinese families and cause autosomal-dominant diffuse nonepidermolytic palmoplantar keratoderma.
Highlights
One of the characteristics of cell membranes is their semi-permeability
These results suggest the aquaporin 5 (AQP5) levels in the submandibular gland (SMG) is maintained by the parasympathetic nerve, and that this water channel in the parotid gland (PG) is translocated to the apical membrane in conjunction with trafficking/docking of secretory granules containing amylase upon stimulation with β-adrenergic agents (Hosoi et al, 2020)
AQP5 is involved in water secretion from the salivary gland acinar cells via a transcellular route
Summary
One of the characteristics of cell membranes is their semi-permeability. This feature allows water to enter and exit cells. Aquaporin (AQP) is a membrane protein with a serpentine-type structure which functions as a water channel. CDNA for AQP5 was first cloned from the salivary gland; it is known as an exocrine-type water channel with a unique tissue expression (Raina et al, 1995).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
