Biomaterial Database

Identity of the calmodulin-binding proteins in bovine lens plasma membranes. 1990

C F Louis, and P Hogan, and L Visco, and G Strasburg

Department of Veterinary Biology, University of Minnesota, St Paul 55108.

Two bovine lens plasma membrane proteins have been identified that bind calmodulin in a Ca2(+)-dependent fashion. Electrophoretic analysis of lens membrane proteins photoaffinity-labeled with benzophenone[125I]calmodulin confirmed our previous observation [Louis, Johnson and Turnquist (1985) Eur. J. Biochem. 150, 271-8] that two major products are formed with Mr = 46 kDa and 36 kDa. Limited proteolysis of lens membrane proteins with chymotrypsin resulted in the formation of a 21-kDa-fragment that was derived from the hydrolysis of the major lens membrane protein MP26; this correlated with the loss of the 46-kDa complex, and the formation of a 41-kDa photoaffinity-labeled complex. Use of the [125I]calmodulin gel overlay procedure confirmed that the 46-kDa and 41-kDa photoaffinity-labeled complexes reflect the interaction of calmodulin with both MP26 and its 21-kDa chymotryptic fragment, respectively. Proteolysis of lens membranes with higher concentrations of chymotrypsin resulted in the hydrolysis of the 18-kDa protein which correlated with the generation of a 12-kDa fragment; this paralleled the loss of the 36-kDa photoaffinity labeled complex and the formation of a 28-kDa-complex. The [125I]calmodulin gel overlay procedure demonstrated that the 36-kDa and 28-kDa photoaffinity-labeled complexes reflect the interaction of calmodulin with the 18-kDa lens membrane protein and its likely 12-kDa chymotryptic fragment, respectively. Identification of these calmodulin-binding proteins suggests that MP26 and the 18-kDa membrane protein are likely candidates for the proposed calcium sensitive, calmodulin-dependent gating of lens fiber cell junctions.

UI	MeSH Term	Description	Entries
D007908	Lens, Crystalline	A transparent, biconvex structure of the EYE, enclosed in a capsule and situated behind the IRIS and in front of the vitreous humor (VITREOUS BODY). It is slightly overlapped at its margin by the ciliary processes. Adaptation by the CILIARY BODY is crucial for OCULAR ACCOMMODATION.	Eye Lens,Lens, Eye,Crystalline Lens
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D002148	Calmodulin-Binding Proteins	Proteins which bind calmodulin. They are found in many tissues and have a variety of functions including F-actin cross-linking properties, inhibition of cyclic nucleotide phosphodiesterase and calcium and magnesium ATPases.	Caldesmon,Calspectin,CaM-BP(80),Caldesmon (77),Calmodulin Binding Proteins,Proteins, Calmodulin-Binding
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs
D000345	Affinity Labels	Analogs of those substrates or compounds which bind naturally at the active sites of proteins, enzymes, antibodies, steroids, or physiological receptors. These analogs form a stable covalent bond at the binding site, thereby acting as inhibitors of the proteins or steroids.	Affinity Labeling Reagents,Labeling Reagents, Affinity,Labels, Affinity,Reagents, Affinity Labeling
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
D001345	Autoradiography	The making of a radiograph of an object or tissue by recording on a photographic plate the radiation emitted by radioactive material within the object. (Dorland, 27th ed)	Radioautography