Diacylglycerol Lactones Targeting the Structural Features That Distinguish the Atypical C1 Domains of Protein Kinase C ζ and ι from Typical C1 Domains

We have isolated and characterized a new human cDNA, coding for a protein kinase, related to the protein kinase C (PKC) gene family. Although this protein kinase shares some homologous sequences and structural features with the four members of the PKC family initially isolated (alpha, beta I, beta II, and gamma), it shows more homology with the recently described PKC-related subfamily, encoded by the cDNAs delta, epsilon, and zeta. The transcript for this gene product, termed PKC-L, is most abundant in lung tissue, less expressed in heart and skin tissue, and exhibited very low expression in brain tissue. Thus, its tissue distribution is different from that described for other mammalian members of the PKC gene family, their expression being enriched in brain tissues. PKC-L is also expressed in several human cell lines, including the human epidermoid carcinoma line A431. The ability of phorbol esters to bind to and stimulate the kinase activity of PKC-L was revealed by introducing the cDNA into COS cells.

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A Novel Diacylglycerol-lactone Shows Marked Selectivityin Vitroamong C1 Domains of Protein Kinase C (PKC) Isoforms α and δ as Well as Selectivity for RasGRP Compared with PKCα

Journal of Biological Chemistry ◽

10.1074/jbc.m414132200 ◽

2005 ◽

Vol 280 (29) ◽

pp. 27329-27338 ◽

Cited By ~ 34

Author(s):

Yongmei Pu ◽

Nicholas A. Perry ◽

Dazhi Yang ◽

Nancy E. Lewin ◽

Noemi Kedei ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Kinase C ◽

Pkc Isoforms ◽

C1 Domains

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Protein Kinase C gamma Mutations Drive Spinocerebellar Ataxia Type 14 by Impairing Autoinhibition

10.1101/2021.06.24.449810 ◽

2021 ◽

Author(s):

Caila A. Pilo ◽

Alexandr P. Kornev ◽

Timothy R. Baffi ◽

Maya T. Kunkel ◽

Liang-Chin Huang ◽

...

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Spinocerebellar Ataxia ◽

Spinocerebellar Ataxia Type ◽

Cell Degeneration ◽

Basal Activity ◽

Kinase C ◽

Protein Kinase C Gamma ◽

Spinocerebellar Ataxia Type 14 ◽

C1 Domains

Spinocerebellar ataxia type 14 (SCA14) is a neurodegenerative disease caused by germline mutations in the diacylglycerol (DG)/Ca2+-regulated protein kinase C gamma (PKCγ), leading to Purkinje cell degeneration and progressive cerebellar dysfunction. The majority of the approximately 50 mutations identified in PKCγ cluster to the DG-sensing C1 domains. Here, we use a FRET-based activity reporter to show that ataxia-associated PKCγ mutations enhance basal activity by compromising autoinhibition. Although impaired autoinhibition generally leads to PKC degradation, the C1 domain mutations protect PKCγ from phorbol ester-induced downregulation. Furthermore, it is the degree of disrupted autoinhibition, not changes in the amplitude of agonist-stimulated activity, that correlate with disease severity. Specifically, a SCA14 mutation in which phenylalanine 48 in the C1A domain is deleted had high basal activity both in cells and in vitro, yet was unresponsive to agonist stimulation. Validating that the pathology arises from disrupted autoinhibition, we show that the degree of impaired autoinhibition correlates inversely with age of disease onset in patients: mutations that cause high basal activity are associated with early onset, whereas those that only modestly increase basal activity, including a previously undescribed mutation D115Y, are associated with later onset. Molecular modeling indicates that almost all SCA14 mutations that are not in the C1 domains are at interfaces with the C1B domain, and bioinformatics analysis reveals that mutations in the C1B domain are under-represented in cancer. Thus, clustering of SCA14 mutations to the C1B domain provides a unique mechanism to enhance PKCγ basal activity while protecting the enzyme from downregulation.

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Synthesis and Binding Selectivity of 7- and 15-Decylbenzolactone-V8 for the C1 Domains of Protein Kinase C Isozymes.

ChemInform ◽

10.1002/chin.200350219 ◽

2003 ◽

Vol 34 (50) ◽

Author(s):

Yu Nakagawa ◽

Kazuhiro Irie ◽

Nobuhiro Yamanaka ◽

Hajime Ohigashi ◽

Ken-ichiro Tsuda

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Binding Selectivity ◽

Kinase C ◽

C1 Domains

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p23/Tmp21 Differentially Targets the Rac-GAP β2-Chimaerin and Protein Kinase C via Their C1 Domains

Molecular Biology of the Cell ◽

10.1091/mbc.e09-08-0735 ◽

2010 ◽

Vol 21 (8) ◽

pp. 1398-1408 ◽

Cited By ~ 18

Author(s):

HongBin Wang ◽

Marcelo G. Kazanietz

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Protein Interactions ◽

Phorbol Esters ◽

Lipid Binding ◽

Kinase C ◽

C1 Domain ◽

Pkc Isozymes ◽

Domain Docking ◽

C1 Domains

The C1 domains in protein kinase C (PKC) isozymes and other signaling molecules are responsible for binding the lipid second messenger diacylglycerol and phorbol esters, and for mediating translocation to membranes. Previous studies revealed that the C1 domain in α- and β-chimaerins, diacylglycerol-regulated Rac-GAPs, interacts with the endoplasmic reticulum/Golgi protein p23/Tmp21. Here, we found that p23/Tmp21 acts as a C1 domain-docking protein that mediates perinuclear translocation of β2-chimaerin. Glu227 and Leu248 in the β2-chimaerin C1 domain are crucial for binding p23/Tmp21 and perinuclear targeting. Interestingly, isolated C1 domains from individual PKC isozymes differentially interact with p23/Tmp21. For PKCε, it interacts with p23/Tmp21 specifically via its C1b domain; however, this association is lost in response to phorbol esters. These results demonstrate that p23/Tmp21 acts as an anchor that distinctively modulates compartmentalization of C1 domain-containing proteins, and it plays an essential role in β2-chimaerin relocalization. Our study also highlights the relevance of C1 domains in protein–protein interactions in addition to their well-established lipid-binding properties.

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