Identification of GIT1/Cat-1 as a substrate molecule of protein tyrosine phosphatase ζ/β by the yeast substrate-trapping system

We used a genetic method, the yeast substrate-trapping system, to identify substrates for protein tyrosine phosphatases ζ (PTPζ/RPTPβ). This method is based on the yeast two-hybrid system, with two essential modifications: conditional expression of protein tyrosine kinase v-src (active src) to tyrosine-phosphorylate the prey proteins and screening by using a substrate-trap mutant of PTPζ (PTPζ-D1902A) as bait. By using this system, several substrate candidates for PTPζ were isolated. Among them, GIT1/Cat-1 (G protein-coupled receptor kinase-interactor 1/Cool-associated, tyrosine-phosphorylated 1) was examined further. GIT1/Cat-1 bound to PTPζ-D1902A dependent on the substrate tyrosine phosphorylation. Tyrosine-phosphorylated GIT1/Cat-1 was dephosphorylated by PTPζ in vitro. Immunoprecipitation experiments indicated that PTPζ-D1902A and GIT1/Cat-1 form a stable complex also in mammalian cells. Immunohistochemical analyses revealed that PTPζ and GIT1/Cat-1 were colocalized in the processes of pyramidal cells in the hippocampus and neocortex in rat brain. Subcellular colocalization was further verified in the growth cones of mossy fibers from pontine explants and in the ruffling membranes and processes of B103 neuroblastoma cells. Moreover, pleiotrophin, a ligand for PTPζ, increased tyrosine phosphorylation of GIT1/Cat-1 in B103 cells. All these results indicate that GIT1/Cat-1 is a substrate molecule of PTPζ.

Conformational trapping in a membrane environment: a regulatory mechanism for protein activity?

Functional regulation of proteins is central to living organisms. Here it is shown that a nonfunctional conformational state of a polypeptide can be kinetically trapped in a lipid bilayer environment. This state is a metastable structure that is stable for weeks just above the phase transition temperature of the lipid. When the samples are incubated for several days at 68 degrees C, 50% of the trapped conformation converts to the minimum-energy functional state. This result suggests the possibility that another mechanism for functional regulation of protein activity may be available for membrane proteins: that cells may insert proteins into membranes in inactive states pending the biological demand for protein function.

Trapping of branched DNA in microfabricated structures.

We have observed electrostatic trapping of tribranched DNA molecules undergoing electrophoresis in a microfabricated pseudo-two-dimensional array of posts. Trapping occurs in a unique transport regimen in which the electrophoretic mobility is extremely sensitive to polymer topology. The arrest of branched polymers is explained by considering their center-of-mass motion; in certain conformations, owing to the constraints imposed by the obstacles a molecule cannot advance without the center of mass first moving a short distance backwards. The depth of the resulting local potential well can be much greater than the thermal energy so that escape of an immobilized molecule can be extremely slow. We summarize the expected behavior of the mobility as a function of field strength and topology and point out that the microfabricated arrays are highly suitable for detecting an extremely small number of branched molecules in a very large population of linear molecules.

Polyurethane foam as trapping agent for airborne pesticides : analytical method development /

"Interagency agreement no. 78-D-XO449."

Canadian wilds : tells about the Hudson's Bay Company, northern Indians and their modes of hunting, trapping, etc. /

Mode of access: Internet.

Historical sketch of the Flathead Indian nation from the year 1813 to 1890. Embracing the history of the establishment of St. Mary's Indian mission in the Bitter Root Valley, Mont. With sketches of the missionary life of Father Ravalli and other early missionaries, wars of the Blackfeet and Flatheads, and sketches of history, trapping and trading in the early days ...

Mode of access: Internet.

City boys in the woods; or, A trapping venture in Maine,

Mode of access: Internet.

The reliable pheasant standard; a practical guide on the culture, breeding, rearing, trapping, preserving ... etc. of pheasants, game birds, ornamental land and water fowl, singing birds, etc.

Mode of access: Internet.

Twenty years on the trap line : being a collection of revised camp notes written at intervals during a twenty years experience in trapping, wolfing and hunting, on the great Northwestern plains /

Mode of access: Internet.

Hunting, fishing and trapping proclamations.

Cover title of some issues: Game and fish law proclamations.

Illinois furbearer trapping survey.

Cover title.

Illinois digest of hunting and trapping regulations.

Description based on: 1996-97; title from cover.

An experimental study of the effects of viscous and capillary forces on the trapping and mobilization of oil drops in capillary constrictions /

Thesis--University of Kansas, Chemical and Petroleum Engineering.