Assuntos
Moléculas de Adesão Celular/imunologia , Sarcoma de Células Dendríticas Foliculares/complicações , Síndromes Paraneoplásicas/etiologia , Pênfigo/etiologia , Adulto , Autoanticorpos/imunologia , Humanos , Japão , Masculino , Síndromes Paraneoplásicas/imunologia , Síndromes Paraneoplásicas/patologia , Pênfigo/imunologia , Pênfigo/patologia , CalininaRESUMO
In the starfish Asterias amurensis, acrosome reaction inducing substance (ARIS) is the main factor responsible for allowing sperm to recognize the egg jelly and begin the acrosome reaction (AR). ARIS is a large proteoglycan-like molecule, and its pentasaccharide repeat, Fragment 1 (Fr. 1), is responsible for inducing AR. Here, we investigated the primary structure of ARIS for the first time in order to improve our understanding of its functionality. Electrophoretic analysis revealed that ARIS is a complex of three proteins, all of which are modified by the Fr. 1 sugar chain. Sequencing indicated that there are two novel, conserved domains in all three ARIS proteins: ARIS N-terminus (AR-N) and ARIS C-terminus (AR-C) domains. We also found that other echinoderms possess ARIS proteins that are capable of inducing the AR for homologous sperm, indicating that ARIS proteins may be a ubiquitous component for echinoderm fertilization. Moreover, we identified ARIS-like genes from Ctenophora to Protochordata.
Assuntos
Asterias/química , Glicoproteínas/química , Animais , Asterias/metabolismo , Feminino , Fertilização/fisiologia , Glicoproteínas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Estrutura Terciária de Proteína , Espermatozoides/química , Espermatozoides/metabolismoRESUMO
In the starfish, Asterias amurensis, three components in the jelly coat of eggs, namely acrosome reaction-inducing substance (ARIS), Co-ARIS and asterosap, act in concert on homologous spermatozoa to induce the acrosome reaction (AR). Molecular recognition between the sperm surface molecules and the egg jelly molecules must underlie signal transduction events triggering the AR. Asterosap is a sperm-activating molecule, which stimulates rapid synthesis of intracellular cGMP, pH and Ca2+. This transient elevation of Ca2+ level is caused by a K+-dependent Na+/Ca2+ exchanger, and the increase of intracellular pH is sufficient for ARIS to induce the AR. The concerted action of ARIS and asterosap could induce elevate intracellular cAMP levels in starfish sperm and the sustained increase in [Ca2+], which is essential for the AR. The signaling pathway induced by these factors seems to be synergistically regulated to trigger the AR in starfish sperm.