The direct measurement of protein kinase C (PKC) activity in isolated membranes using a selective peptide substrate

Chakravarthy, Balu; Bussey, Alexandra; Whitfield, J. F.; Sikorska, Marianna; Williams, Robert; Durkin, Jon P.

doi:10.1016/0003-2697(91)90130-l

Cited by 112 publications

(96 citation statements)

References 26 publications

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“…Alkaline phosphatase-conjugated goat anti-rabbit IgG was supplied by Boehringer Mannheim Biochemicals. The PKCselective peptide Ac-FKKSFKL-NH 2 (Chakravarthy et al, 1991) was synthesized by the Biochemistry Biotechnology Facility at Indiana University. The antibodies against PKCa and PKC consensus sequences are listed in Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…To test whether PKC in photoreceptor outer segments belongs to the subtype of conventional (Ca2-and lipid-regulated), novel (lipid-regulated), or atypical (activity requires phosphatidylserine) isozymes, the cofactor dependence for its phosphorylation of a PKC-selective peptide (Chakravarthy et al, 1991) was measured. Figure 1 shows that phosphorylation of the peptide was stimulated by both Ca2~and lipid, indicating that the activity in rod outer segments is catalyzed by a conventional PKC.…”

Section: Pkc Activity In Photoreceptor Outer Segmentsmentioning

confidence: 99%

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Characterization of Protein Kinase C in Photoreceptor Outer Segments

Williams

Liu

Schlamp

et al. 1997

Journal of Neurochemistry

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Protein kinase C (PKC) has been implicated in regulating several proteins involved in phototransduction. This contribution characterizes the biochemical and immunological properties of PKC isozyme(s) in the photoreceptor outer segment. Activity measurements revealed that at least 85% of the PKC in this specialized compartment belongs to the subfamily of Ca 2~-regulated(conventional) PKCs. Of the known Ca2-dependent PKCs, only PKCa was immunodetected by western blot analysis of rod outer segment proteins. However, the ratio of immunoreactivity to enzyme activity for rod outer segment PKC was no more than 40% of that for brain PKC, using antibodies against conventional PKCs. Therefore, at least half the Ca2~/lipid-stimulatedactivity in rod outer segment preparations cannot be accounted for by the known isozymes, suggesting the presence of a previously uncharacterized isozyme. Despite extensive tests using a variety of antibodies against different domains of PKCa, PKCn could not be detected in rod outer segments by immunofluorescence of retinal sections. In summary, our data reveal that most of the PKC in photoreceptor outer segments is of the conventional type and that most, if not all, of this conventional PKC activity comes from a novel isozyme (s). Key Words: Retina-PhotoreceptorOuter segment-Protein kinase C-lsozymes-Phorbol ester.

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Section: Methodsmentioning

confidence: 99%

Section: Pkc Activity In Photoreceptor Outer Segmentsmentioning

confidence: 99%

Characterization of Protein Kinase C in Photoreceptor Outer Segments

Williams

Liu

Schlamp

et al. 1997

Journal of Neurochemistry

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“…Although nodulin 26 is phosphorylated in planta by CDPK (Weaver et al, 1991;Weaver and Roberts, 1992), it is less clear which protein kinase might phosphorylate the protein in oocytes, because animal tissues lack this enzyme (Harmon et al, 2000). Ser-262 within the hydrophilic C-terminal domain of nodulin 26 resembles sequences recognized by animal protein kinase C ␣ (PKC ␣ ) (Chakravarthy et al, 1991). Furthermore, another MIP protein, aquaporin 0, is phosphorylated by PKC on an identically placed Ser residue within its C terminus (Lampe and Johnson, 1989).…”

Section: Analysis Of Phosphorylation Effects In Oocytesmentioning

confidence: 99%

Phosphorylation of Soybean Nodulin 26 on Serine 262 Enhances Water Permeability and Is Regulated Developmentally and by Osmotic Signals

et al. 2003

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Soybean nodulin 26 is expressed and targeted to the symbiosome membrane of nitrogen-fixing nodules, where it forms an aquaporin channel with a modest water transport rate. In this study, we show that the phosphorylation of nodulin 26 on Ser-262, which is catalyzed by a symbiosome membrane-associated calcium-dependent protein kinase, stimulates its intrinsic water transport rate. Furthermore, using a phosphospecific antibody, we have elucidated the developmental appearance and regulation of nodulin 26 phosphorylation in vivo. Although nodulin 26 protein is detected first in differentiating infected cells (16 days), phosphorylated nodulin 26 does not become pronounced until infected cell maturation (25 days). Phosphorylation is sustained at steady state levels until entry into senescence. Nodulin 26 phosphorylation is enhanced further by osmotic stresses (water deprivation and salinity). Thus, the phosphorylation of nodulin 26 coincides with the establishment of mature nitrogen-fixing symbiosomes, is regulated by osmotic stresses that induce calcium-signaling pathways, and appears to be part of the adaptive responses of infected cells to osmotic challenge.

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“…The activity of protein kinase C towards phospborylation of a peptide substrate [22] was measured in the presence of Ca 2+ (1.2 mM) and Triton X-100 (0.1%) mixed micelles containing 15 mol% phosphatidylserine and 5 tool% either 1,2-dioleoylsn-glycerol, 1,3-dioleoyl-sn-glycerol, or 2,3-dioleoyl-sn-glycerol, as described [18].…”

Section: Protein Kinase C Assaymentioning

confidence: 99%

Diacylglycerol directly stimulates the insulin receptor tyrosine kinase

Arnold

Newton

1996

FEBS Letters

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Studies with detergent:lipid mixed micelles reveal that diacylglycerol directly stimulates the intrinsic tyrosine kinase activity of the insulin receptor. Kinetic analyses indicate that diacylglycerol activates the kinase by causing a marked increase in the affinity of the receptor for insulin. In contrast, diacylglycerol has no effect on the insulin receptor's catalytic activity or its affinity for ATP. Stimulation of the insulin receptor is not a result of protein kinase C activation. First, phorbol myristate acetate, a potent activator of protein kinase C, has no effect on insulin receptor activity. Second, the activation by diacylglycerol is not stereospecific, in marked contrast to the specificity for 1,2-diacylsn-glycerol in the activation of protein kinase C. Because circulating levels of insulin are below the/Ca of the insulin receptor for insulin, the ability of diacylglycerol to modulate the affinity of the receptor for ligand suggests that increases in cellular levels of diacylglycerol directly sensitize the receptor to insulin.

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The direct measurement of protein kinase C (PKC) activity in isolated membranes using a selective peptide substrate

Cited by 112 publications

References 26 publications

Characterization of Protein Kinase C in Photoreceptor Outer Segments

Characterization of Protein Kinase C in Photoreceptor Outer Segments

Phosphorylation of Soybean Nodulin 26 on Serine 262 Enhances Water Permeability and Is Regulated Developmentally and by Osmotic Signals

Diacylglycerol directly stimulates the insulin receptor tyrosine kinase

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