Article Information
PubMed
Related Articles
- Lipid Lateral Organization in Fluid Interfaces Controls the ...Lipid Lateral Organization in Fluid Interfaces Controls the Rate of Colipase Association
Biophysical Journal, Volume 81, Issue 6, 1 December 2001, Pages 3387-3397
Istvan P. Sugar, Nancy K. Mizuno, Maureen M. Momsen and Howard L. Brockman
AbstractColipase, a cofactor of pancreatic triacylglycerol lipase, binds to surfaces of lipolysis reactants, like fatty acid and diacylglycerol, but not to the nonsubstrate phosphatidylcholine. The initial rate of colipase binding to fluid, single-phase lipid monolayers was used to characterize the interfacial requirements for its adsorption. Colipase adsorption rates to phosphatidylcholine/reactant mixed monolayers depended strongly on lipid composition and packing. Paradoxically, reactants lowered colipase adsorption rates only if phosphatidylcholine was present. This suggests that interactions between phosphatidylcholine and reactants create dynamic complexes that impede colipase adsorption. Complex formation was independently verified by physical measurements. Colipase binding rate depends nonlinearly on the two-dimensional concentration of phosphatidylcholine. This suggests that binding is initiated by a cluster of nonexcluded surface sites smaller than the area occupied by a bound colipase. Binding rates are mathematically consistent with this mechanism. Moreover, for each phosphatidylcholine-reactant pair, the complex area obtained from the analysis of binding rates agrees well with the independently measured collapse area of the complex. The dynamic complexes between phosphatidylcholine and lipids, like diacylglycerols, exist independently of the presence of colipase. Thus, our results suggest that lipid complexes may regulate the fluxes of other proteins to membranes during, for example, lipid-mediated signaling events in cells.
Abstract | Full Text | PDF (144 kb) - A colipase fold in the carboxy-terminal domain of the Wnt an...A colipase fold in the carboxy-terminal domain of the Wnt antagonists – the Dickkopfs
Current Biology, Volume 8, Issue 14, 2 July 1998, Pages R477-R479
L. Aravind and Eugene V. Koonin
Full Text | PDF (285 kb) - Sequence homology between Wingless/Wnt-1 and a lipid-binding...Sequence homology between Wingless/Wnt-1 and a lipid-binding domain in secreted phospholipase A2
Current Biology, Volume 9, Issue 10, 20 May 1999, Pages R353-R355
Frieda Reichsman, Helen M. Moore and Susan Cumberledge
Full Text | PDF (97 kb) - …more
Copyright © 1996 The Biophysical Society. All rights reserved.
Biophysical Journal, Volume 71, Issue 6, 3421-3429, 1 December 1996
doi:10.1016/S0006-3495(96)79536-X
Research Article
The affinities of procolipase and colipase for interfaces are regulated by lipids
G.D. Schmit, M.M. Momsen, W.G. Owen, S. Naylor, A. Tomlinson, G. Wu, R.E. Stark and H.L. Brockman
Hormel Institute, University of Minnesota, Austin 55912, USA.
Abstract
It has been suggested that at physiological pH, the trypsin-catalyzed activation of the lipase cofactor, procolipase, to colipase has no consequence for intestinal lipolysis and serves primarily to release the N-terminal pentapeptide, enterostatin, a satiety factor (Larsson, A., and C. Erlanson-Albertsson 1991. The effect of pancreatic procolipase and colipase on pancreatic lipase activation. Biochim. Biophys. Acta 1083:283–288). This hypothesis was tested by measuring the adsorption of [14C]colipase to monolayers of 1-stearoyl-2-oleoyl-sn-3-glycerophosphocholine and 13, 16-cis, cis-docosadienoic acid in the presence and absence of procolipase. With saturating [14C]colipase in the subphase, the surface excess of [14C]colipase is 29% higher than that of procolipase, indicating that colipase packs more tightly in the interface. With [14C]colipase-procolipase mixtures, the proteins compete equally for occupancy of the argon-buffer interface. However, if a monolayer of either or both lipids is present, [14C]colipase dominates the adsorption process, even if bile salt is present in the subphase. If [14C]colipase and procolipase are premixed for > 12 h at pH approximately 8, this dominance is partial. If they are not premixed, procolipase is essentially excluded from the interface, even if procolipase is added before [14C]colipase. These results suggest that the tryptic cleavage of the N-terminal pentapeptide of procolipase may be of physiological consequence in the intestine.
