The C1 domain of protein kinase C as a lipid bilayer surface sensing module.
The activity of membrane-associated protein kinase C (PKC) is tightly controlled by the physical properties of the membrane lipid bilayer, in particular, curvature stress, which is induced by bilayer-destabilizing lipid components. An important example of this is the weakened lipid headgroup interactions induced by phosphatidylethanolamine (PE) and cholesterol. In this work our previous observation with a mixed isoform PKC showing a biphasic dependence of activity as a function of membrane curvature stress [Slater et al. (1994) J. Biol. Chem. 269, 4866-4871] was here extended to individual isoforms. The Ca(2+)-dependent PKCalpha, PKCbeta, and PKCgamma, along with Ca(2+)-independent PKCdelta, but not PKCepsilon or PKCzeta, displayed a biphasic activity as a function of membrane PE content. The fluorescence anisotropy of N-(5-dimethylaminonaphthalene-1-sulfonyl)dioleoylphosphatidylserine (dansyl-PS), which probes the lipid environment of PKC, also followed a biphasic profile as a function of PE content for full-length PKCalpha, PKCbetaIotaIota, and PKCgamma as did the isolated C1 domain of PKCalpha. In addition, the rotational correlation time of both PKCalpha and PKCdelta C1-domain-associated sapintoxin D, a fluorescent phorbol ester, was also a biphasic function of membrane lipid PE content. These results indicate that the C1 domain acts as a sensor of the bilayer surface properties and that its conformational response to these effects may directly underlie the resultant effects on enzyme activity.
Ho
C
C
Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
Slater
S J
SJ
Stagliano
B
B
Stubbs
C D
CD
D000818:Animals; D001921:Brain / Q000201:enzymology; D005454:Fluorescence Polarization; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010718:Phosphatidylserines / Q000737:chemistry; D011493:Protein Kinase C / Q000737:chemistry* / Q000378:metabolism*; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D007527:Isoenzymes; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D011994:Recombinant Proteins; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine; C497260:Prkcd protein, rat; C087857:protein kinase C gamma; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; C028694:1-palmitoyl-2-oleoylphosphatidylcholine