CABYR, a Novel Calcium-Binding Tyrosine Phosphorylation-Regulated Fibrous Sheath Protein Involved in Capacitation

Developmental Biology

Arabinda Mandal¹  John C. Herr¹  V.Anne Westbrook¹  Soren Naaby-Hansen¹  Young-Howan Kim¹  Leigh Ann Bush¹  Buer Sen¹  Scott A. Coonrod¹  Charles J. Flickinger¹  Michael J. Wolkowicz¹  Jagathpala Shetty¹  Kenneth L. Klotz¹ 

[1] Ludwig Institute for Cancer Research, Royal Free and University College School of Medicine, London, W1P 8BT, United Kingdom

关键词: CABYR;    spermatozoa;    capacitation;    calcium-binding protein;    fibrous sheath;    tyrosine phosphorylation;    postmeiotic expression;   

DOI  :  10.1006/dbio.2001.0527

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Toreachfertilizationcompetence,spermundergoanincompletelyunderstoodseriesofmorphologicalandmolecularmaturationalprocesses,termedcapacitation,involving,amongotherprocesses,proteintyrosinephosphorylationandincreasedintracellularcalcium.Hyperactivatedmotilityandanabilitytoundergotheacrosomereactionserveasphysiologicalendpointstoassesssuccessfulcapacitation.Wereportherethatacidic(pI4.0)86-kDaisoformsofanovel,polymorphic,testis-specificprotein,designatedcalcium-bindingtyrosinephosphorylation-regulatedprotein(CABYR),weretyrosinephosphorylatedduringinvitrocapacitationandbound45Caon2Dgels.Acidic86-kDacalcium-bindingformsofCABYRincreasedduringinvitrocapacitation,andcalciumbindingtotheseacidicformswasabolishedbydephosphorylationwithalkalinephosphatase.SixvariantsofCABYRcontainingtwocodingregions(CR-AandCR-B)wereclonedfromhumantestiscDNAlibraries,includingfivevariantswithalternativesplicedeletions.AmotifhomologoustotheRIIdimerizationdomainofPK-AwaspresentintheN-terminusofCR-AinfourCABYRvariants.AsingleputativeEFhandlikemotifwasnotedinCR-Aataas197–209,whilesevenpotentialtyrosinephosphorylation-likesiteswerenotedinCR-AandfourinCR-B.Pro-X-X-Pro(PXXP)moduleswereidentifiedintheN-andC-terminiofCR-AandCR-B.CABYRlocalizestotheprincipalpieceofthehumanspermflagelluminassociationwiththefibroussheathandisthefirstdemonstrationofaspermproteinthatgainscalcium-bindingcapacitywhenphosphorylatedduringcapacitation.

【 授权许可】

Unknown