Isolation, Cloning, and Characterization of a New Mammalian Coronin Family Member, Coroninse, Which Is Regulated within the Protein Kinase C Signaling Pathway*
- From the Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912-3175
Abstract
In order to understand the regulatory role of protein kinase C (PKC) in secretory epithelia, it is necessary to identify and characterize specific downstream targets. We previously identified one such protein in studies of gastric parietal cells. This protein was referred to as pp66 because it migrated with an apparent molecular mass of 66 kDa on SDS-polyacrylamide gels. The phosphorylation of pp66 is increased by the cholinergic agonist, carbachol, and by the PKC activator, phorbol-12-myristate-13-acetate, in a calcium-independent manner. In this study, we have purified pp66 to homogeneity and cloned the complete open reading frame. GenBankTM searches revealed a 45% homology with theDictyostelium actin-binding protein, coronin, and ∼67% homology with the previously cloned human and bovine coronin-like homologue, p57. pp66 appears to be most highly expressed in the gastrointestinal mucosa and in kidney and lung. Confocal microscopic studies of an enhanced green fluorescent protein fusion construct of pp66 in cultured parietal cells and in Madin-Darby canine kidney cells indicate that pp66 preferentially localizes in F-actin-rich regions. On the basis of our findings, we propose that pp66 may play an important, PKC-dependent role in regulating membrane/cytoskeletal rearrangements in epithelial cells. We have tentatively named this protein coroninse, because it appears to be highly expressed in secretory epithelia.
Footnotes
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↵* This work was supported by National Institutes of Health Grants R37 DK31900 (to C. S. C.) and F32 DK 09447 (to J. A. P.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) AF056312 and AF100414.
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↵‡ To whom correspondence should be addressed: Inst. of Molecular Medicine and Genetics, Sanders R & E Bldg., Rm. CB 2803, Medical College of Georgia, Augusta, GA 30912-3175. Tel.: 706-721-0681; Fax: 706-721-7915; E-mail: cchew{at}mailer.mcg.edu.
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↵2 J. A. Parente, Jr., X. Chen, C. Zhou, A. C. Petropoulos, and C. S. Chew, unpublished observations.
- Abbreviations:
- PKC
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protein kinase C
- EGFP
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enhanced green fluorescent protein
- PCR
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polymerase chain reaction.
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- Received September 15, 1998.
- Revision received October 29, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
