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Slimed! Better understanding the role of aquaporin in the slime gland of hagfish
Author(s) -
Lane Jim,
Torenvliet Alyne,
Edmunds Mary,
Schimnowski Ava
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.lb145
Subject(s) - hagfish , vesicle , aquaporin , microbiology and biotechnology , biology , mucin , chemistry , membrane , biochemistry , vertebrate , gene
Hagfish are a species of small marine vertebrates that have experienced little evolutionary change for 300 million years due to their effective defense mechanism. This mechanism has the potential to be a component of many major medical advancements as well as airbag technology and textiles. When threatened, a hagfish will rapidly deploy a slime gland exudate that expands in a fraction of a second and clogs the gills of its predator, suffocating it. This is a two‐part process involving the unraveling of thread skeins and bursting of mucin vesicles. Our research focuses on the mucin vesicles and how the membrane protein Hagfish Aquaporin 4 (hfAQP4) controls the rupturing process. When a mucin vesicle comes in contact with seawater, Ca2+ions contained in the water open Ca2+ activated protein channels within the vesicle membrane and allow for a variety of seawater ions to enter the vesicle. This changes the osmotic balance within the vesicle to favor the influx of water molecules which flood the cell through the hfAQP4 channel. The vesicle becomes overfilled with water and ruptures, releasing the slime. We continued to explore the role of hfAQP4 in this process and found research done by Cutler, et. al that compared Aquaporin 4 (AQP4) of human, rat, chicken, xenofish, zebrafish, dogfish and hagfish. This research found that hfAQP4 differs more from human aquaporin 4 (hAQP4) than any of the other aquaporins studied. In order to better understand the function of hfAQP4 in the slime release process, we will identify similarities and differences between hAQP4 and hfAQP4. Also, using the hAPQ4 pdb, 3GD8, we can use the molecular modeling software, jmol, to highlight the variations compared to hfAQP4. Our research was narrowed down to hfAQP4 due to findings that confirmed the role of hfAQP4 in the slime deployment process. When mercuric chloride (HgCl2), an aquaporin inhibitor, is added to the water that the slime is being deployed into, the vesicles membranes do not rupture which proves the involvement of hfAQP4 in this process. The (HgCl2) is very successful in inhibiting AQP4 because of the location of the amino acid: Cysteine 178. In Aquaporin 1 (AQP1), Cysteine 189 is located at the constriction of the pore, and is not easily accessible to the HgCl2. In AQP4, however, the cysteine residue is located in cytoplasmic loop D at the location of Cysteine 178, and is much more accessible to the HgCl2. This causes AQP4 to be more rapidly inhibited by HgCl2 than AQP1. The Mahtomedi MSOE Center for BioMolecular Modeling MAPS Team used 3‐D modeling and printing technology to examine structure‐function relationships of hfAQP4. The visual model will be a valuable tool in developing our story. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .