Biomaterial Database

Purification and characterization of a novel chemorepellent receptor from Tetrahymena thermophila. 1998

H G Kuruvilla, and T M Hennessey

State University of New York at Buffalo, Department of Biological Sciences 14260, USA.

Chemosensory transduction and adaptation are important aspects of signal transduction mechanisms in many cell types, ranging from prokaryotes to differentiated tissues such as neurons. The eukaryotic ciliated protozoan, Tetrahymena thermophila, is capable of responding to both chemoattractants (O'Neill et al., 1985; Leick, 1992; Kohidai, Karsa & Csaba, 1994, 1995) and chemorepellents (Francis & Hennessey, 1995; Kuruvilla, Kim & Hennessey, 1997). An example of a nontoxic, depolarizing chemorepellent in Tetrahymena is extracellular lysozyme (Francis & Hennessey, 1995; Hennessey, Kim & Satir, 1995). Lysozyme is an effective chemorepellent at micromolar concentrations, binds to a single class of externally facing membrane receptors and prolonged exposure (10 min) produces specific chemosensory adaptation (Kuruvilla et al., 1997). We now show that this lysozyme response is initiated by a depolarizing chemoreceptor potential in Tetrahymena and we have purified the membrane lysozyme receptor by affinity chromatography of solubilized Tetrahymena membrane proteins. The solubilized, purified protein is 42 kD and it exhibits saturable, high affinity lysozyme binding. Polyclonal antibodies raised against this 42 kD receptor block the in vivo lysozyme chemoresponse. This is not only the first time that a chemoreceptor potential has been recorded from Tetrahymena but also the first time that a chemorepellent receptor has been purified from any unicellular eukaryote.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009113	Muramidase	A basic enzyme that is present in saliva, tears, egg white, and many animal fluids. It functions as an antibacterial agent. The enzyme catalyzes the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. EC 3.2.1.17.	Lysozyme,Leftose,N-Acetylmuramide Glycanhydrolase,Glycanhydrolase, N-Acetylmuramide,N Acetylmuramide Glycanhydrolase
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D016808	Tetrahymena thermophila	A species of ciliate protozoa used in genetic and cytological research.	Tetrahymena thermophilas,thermophilas, Tetrahymena