Nowa, a novel protein with minicollagen Cys-rich domains, is involved in nematocyst formation in Hydra.
The novel protein Nowa was identified in nematocysts, explosive organelles of Hydra, jellyfish, corals and other CNIDARIA: Biogenesis of these organelles is complex and involves assembly of proteins inside a post-Golgi vesicle to form a double-layered capsule with a long tubule. Nowa is the major component of the outer wall, which is formed very early in morphogenesis. The high molecular weight glycoprotein has a modular structure with an N-terminal sperm coating glycoprotein domain, a central C-type lectin-like domain, and an eightfold repeated cysteine-rich domain at the C-terminus. Interestingly, the cysteine-rich domains are homologous to the cysteine-rich domains of minicollagens. We have previously shown that the cysteines of these minicollagen cysteine-rich domains undergo an isomerization process from intra- to intermolecular disulfide bonds, which mediates the crosslinking of minicollagens to networks in the inner wall of the capsule. The minicollagen cysteine-rich domains present in both proteins provide a potential link between Nowa in the outer wall and minicollagens in the inner wall. We propose a model for nematocyst formation that integrates cytoskeleton rearrangements around the post-Golgi vesicle and protein assembly inside the vesicle to generate a complex structure that is stabilized by intermolecular disulfide bonds.
Engel
Ulrike
U
Institute of Zoology, Darmstadt University of Technology, 64287 Darmstadt, Germany.
Ozbek
Suat
S
Streitwolf-Engel
Ruth
R
Petri
Barbara
B
Lottspeich
Friedrich
F
Holstein
Thomas W
TW
Oezbek
Suat
S
Engel
Ruth
R
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000954:Antigens, Surface / Q000737:chemistry / Q000378:metabolism; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D006031:Glycosylation; D006829:Hydra / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008954:Models, Biological; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D017386:Sequence Homology, Amino Acid
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D004220:Disulfides; D006023:Glycoproteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D003094:Collagen; D003545:Cysteine