Co-localization and functional coupling of creatine kinase B and gastric H+/K+-ATPase on the apical membrane and the tubulovesicular system of parietal cells

Abstract

Immunogold labelling of creatine kinase B (BB-CK) and gastric H+/K(+)-ATPase in the parietal cells of the stomach revealed colocalization of these two enzymes on the apical membrane and the membranes of the tubulovesicular system. Upon fractionation of hog parietal cells, a specific fraction of the BB-CK proteins remained associated with the purified vesicles, in which gastric H+/K(+)-ATPase is highly enriched. The BB-CK present in this highly purified preparation was able to support pronounced H+/K(+)-ATPase activity in K(+)-loaded vesicles in the presence of phosphocreatine and ADP, although only low levels of ATP were measured. In contrast, when pyruvate kinase, phosphoenolpyruvate and ADP were used as an ATP-generating system to sustain similar levels of H+/K(+)-ATPase activity, ATP levels were more than 10-fold higher. Changing the experimental conditions such that ATP levels were the same for both systems resulted in significantly elevated H+/K(+)-ATPase activities in the BB-CK/phosphocreatine system in comparison with the pyruvate kinase/phosphoenolpyruvate system. These results indicate that gastric H+/K(+)-ATPase has preferential access to ATP generated by creatine kinase co-localized on the membranes of the vesicles.

Creatine Kinase in Human Retinal Pigment Epithelium

“…CK activity has been shown to maintain high local ATP concentration to fuel this active ion transport. Predominant localization to either apical (Keller and Gordon, 1991 ;Sistermans et al, 1995) or basolateral (Friedman and Roberts, 1992) membrane has been observed in different epithelia.…”

“…As a corollary of this model, the socalled cytosolic forms of creatine kinase (MM and BB) must be spatially localized. Abundant evidence indicates that both MM-CK and BB-CK can form specific, stable associations with both plasma and intracellular membranes (Clark et al, 1993 ;Keller and Gordon, 1991 ;Korge et al, 1993 ;Korge and Campbell, 1994 ;Lim et al, 1983 ;Perryman et al, 1985 ;Rossi et al, 1990 ;Sistermans et al, 1995 ;Wallimann and Hemmer, 1994).…”

“…It has been proposed that creatine kinase is localized to specific subcellular domains of high-energy usage. Thus, creatine kinase is an important metabolic component in cells with highly compartmentalized energy demands, such as skeletal muscle, neurons, photoreceptors and transporting epithelia Roberts, 1992, 1994 ;Keller and Gordon, 1991 ;Korge et al, 1993 ;Korge and Campbell, 1994 ;Lim et al, 1983 ;Perryman et al, 1985 ;Rossi et al, 1990 ;Sistermans et al, 1995 ;Wallimann and Hemmer, 1994 ;Wallimann et al, 1986). Four isoforms of the enzyme have been described.…”

“…This enzyme functions as part of a system that buffers ATP concentration during periods of high energy usage, and is of primary importance in cell types with high, yet fluctuating metabolic demands (Wallimann and Hemmer, 1994). Though traditionally considered to be a cytosolic enzyme, creatine kinase has been shown to form specific associations with both intracellular and plasma membranes (Clark et al, 1993 ;Keller and Gordon, 1991 ;Korge, Byrd and Campbell, 1993 ;Korge and Campbell, 1994 ;Lim et al, 1983 ;Perryman et al, 1985 ;Rossi et al, 1990 ;Sistermans et al, 1995 ;Wallimann and Hemmer, 1994). It has been proposed that creatine kinase is localized to specific subcellular domains of high-energy usage.…”

Essential Role of Newly Synthesized ATP for Cyclic GMP-Induced Relaxation in .ALPHA.-Toxin Permeabilized Smooth Muscle of Rat Proximal Colon.

“…Functional coupling between and creatine kinase is also reported in the parietal cells of the stomach (Sistermans et al, 1995). Thus, ATP regeneration by creatine kinase is necessary for many cell functions.…”