Identification, Localization, and Functional Implications of an Abundant Nematode Annexin

Cultures of the nematode C. elegans were examined for the presence of calcium-dependent, phospholipid-binding proteins of the annexin class. A single protein of apparent mass on SDS-polyacrylamide gels of 32 kD was isolated from soluble extracts of nematode cultures on the basis of its ability to bi...

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Bibliographic Details
Published in:The Journal of cell biology 1996-03, Vol.132 (6), p.1079-1092
Main Authors: Creutz, Carl E., Snyder, Sandra L., Daigle, Scott N., Redick, Jan
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Annexins
Annexins - analysis
Annexins - genetics
Antibodies
Antiserum
Base Sequence
Caenorhabditis elegans
Caenorhabditis elegans - chemistry
Caenorhabditis elegans - ultrastructure
Caenorhabditis elegans Proteins
Cell Membrane - chemistry
Cell Membrane - ultrastructure
Cellular biology
Chromosome Mapping
Complementary DNA
DNA, Complementary - genetics
Female
Gels
Genes
Genes, Helminth
Genitalia, Female - chemistry
Genitalia, Female - ultrastructure
Helminth Proteins - analysis
Helminth Proteins - genetics
Helminth Proteins - physiology
Immunohistochemistry
Microscopy, Fluorescence
Microscopy, Immunoelectron
Molecular Sequence Data
Nematodes
P branes
Pharynx
Proteins
Recombinant Proteins - genetics
Species Specificity
Uterus
Worms
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Summary:Cultures of the nematode C. elegans were examined for the presence of calcium-dependent, phospholipid-binding proteins of the annexin class. A single protein of apparent mass on SDS-polyacrylamide gels of 32 kD was isolated from soluble extracts of nematode cultures on the basis of its ability to bind to phospholipids in a calcium-dependent manner. After verification of the protein as an annexin by peptide sequencing, an antiserum to the protein was prepared and used to isolate a corresponding cDNA from an expression library in phage λ gt11. The encoded protein, herein referred to as the nex-1 annexin, has a mass of 35 kD and is 36-42% identical in sequence to 10 known mammalian annexins. Several unique modifications were found in the portions of the sequence corresponding to calcium-binding sites. Possible phosphorylation sites in the NH2-terminal domain of the nematode annexin correspond to those of mammalian annexins. The gene for this annexin (nex-1) was physically mapped to chromosome III in the vicinity of the dpy-17 genetic marker. Two other annexin genes (nex-2 and nex-3) were also identified in chromosome III sequences reported by the nematode genomic sequencing project. The nex-1 annexin was localized in the nematode by immunofluorescence and by electron microscopy using immunogold labeling. The protein is associated with membrane systems of the secretory gland cells of the pharynx, with sites of cuticle formation in the grinder in the pharynx, with yolk granules in oocytes, with the uterine wall and vulva, and with membrane systems in the spermathecal valve. The presence of the annexin in association with the membranes of the spermathecal valve suggests a novel function of the protein in the folding and unfolding of these membranes as eggs pass through the valve. The localizations also indicate roles for the annexin corresponding to those proposed in mammalian systems in membrane trafficking, collagen deposition, and extracellular matrix formation.
ISSN:0021-9525
1540-8140
DOI:10.1083/jcb.132.6.1079