PMID:9580562

Citation	Koch, AW, Holstein, TW, Mala, C, Kurz, E, Engel, J and David, CN (1998) Spinalin, a new glycine- and histidine-rich protein in spines of Hydra nematocysts. J. Cell. Sci. 111 ( Pt 11):1545-54
Abstract	Here we present the cloning, expression and immunocytochemical localization of a novel 24 kDa protein, designated spinalin, which is present in the spines and operculum of Hydra nematocysts. Spinalin cDNA clones were identified by in situ hybridization to differentiating nematocytes. Sequencing of a full-length clone revealed the presence of an N-terminal signal peptide, suggesting that the mature protein is sorted via the endoplasmic reticulum to the post-Golgi vacuole in which the nematocyst is formed. The N-terminal region of spinalin (154 residues) is very rich in glycines (48 residues) and histidines (33 residues). A central region of 35 residues contains 19 glycines, occurring mainly as pairs. For both regions a polyglycine-like structure is likely and this may be stabilized by hydrogen bond-mediated chain association. Similar sequences found in loricrins, cytokeratins and avian keratins are postulated to participate in formation of supramolecular structures. Spinalin is terminated by a basic region (6 lysines out of 15 residues) and an acidic region (9 glutamates and 9 aspartates out of 32 residues). Western blot analysis with a polyclonal antibody generated against a recombinant 19 kDa fragment of spinalin showed that spinalin is localized in nematocysts. Following dissociation of the nematocyst's capsule wall with DTT, spinalin was found in the insoluble fraction containing spines and the operculum. Immunocytochemical analysis of developing nematocysts revealed that spinalin first appears in the matrix but then is transferred through the capsule wall at the end of morphogenesis to form spines on the external surface of the inverted tubule and the operculum.
Links	PubMed
Keywords	Amino Acid Sequence; Animals; Base Sequence; Cloning, Molecular; Glycine; Histidine; Hydra/genetics; Hydra/metabolism; Immunohistochemistry; Molecular Sequence Data; Proteins/genetics; Proteins/isolation & purification; Proteins/metabolism; Sequence Analysis
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
9CNID:O45025	part_of	GO:0042151: nematocyst	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
HYDVU:O45025		GO:0042151: nematocyst	ECO:0000314:		C		Figure 6.	complete CACAO 4114
HYDVU:O45025	part_of	GO:0042151: nematocyst	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete

References

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