title: Characterisation of several ankyrin repeat protein variant 2, a phosphoprotein phosphatase 1-interacting protein, in testis and spermatozoa.
abstract: Phosphoprotein phosphatase 1 (PPP1) catalytic subunit gamma 2 (PPP1CC2), a PPP1 isoform, is largely restricted to testicular germ cells and spermatozoa. The key to understanding PPP1 regulation in male germ cells lies in the identification and characterisation of its interacting partners. This study was undertaken to determine the expression patterns of the several ankyrin repeat protein variant 2 (SARP2), a PPP1-interacting protein, in testis and spermatozoa. SARP2 was found to be highly expressed in testis and spermatozoa, and its interaction with human spermatozoa endogenous PPP1CC2 was confirmed by immunoprecipitation. Expression analysis by RT-qPCR revealed that SARP2 and PPP1CC2 mRNA levels were significantly higher in the spermatocyte fraction. However, microscopy revealed that SARP2 protein was only present in the nucleus of elongating and mature spermatids and in spermatozoa. In spermatozoa, SARP2 was prominently expressed in the connecting piece and flagellum, as well as, to a lesser extent, in the acrosome. A yeast two-hybrid approach was used to detect SARP2-interacting proteins and a relevant interaction with a novel sperm-associated antigen 9 (SPAG9) variant, a testis and spermatozoa-specific c-Jun N-terminal kinase-binding protein, was validated in human spermatozoa. Given the expression pattern of SARP2 and its association with PPP1CC2 and SPAG9, it may play a role in spermiogenesis and sperm function, namely in sperm motility and the acrosome reaction.
authors.affiliation: Laboratory of Signal Transduction, Biology Department and Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Joana Vieira
authors.initials: JV
authors.lastname: Silva
authors.affiliation: Laboratory of Signal Transduction, Biology Department and Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Korrodi-Gregório
authors.affiliation: Institute for Anatomy and Experimental Morphology, Center for Experimental Medicine, University Hamburg-Eppendorf, D-20246 Hamburg, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Luers
authors.affiliation: Laboratory of Signal Transduction, Biology Department and Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Cardoso
authors.affiliation: Infante D. Pedro CHBV Hospital, 3810-193 Aveiro, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Patrício
authors.affiliation: Infante D. Pedro CHBV Hospital, 3810-193 Aveiro, Portugal.
authors.forename: Nuno
authors.initials: N
authors.lastname: Maia
authors.affiliation: Laboratory of Signal Transduction, Biology Department and Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Edgar F
authors.initials: EF
authors.lastname: da Cruz E Silva
authors.affiliation: Laboratory of Signal Transduction, Biology Department and Institute for Research in Biomedicine - iBiMED, Health Sciences Program, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Fardilha
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology; D017089:Ankyrin Repeat; D006801:Humans; D008297:Male; D054645:Protein Phosphatase 1 / Q000502:physiology*; D013081:Sperm Motility; D013091:Spermatogenesis; D013094:Spermatozoa / Q000502:physiology*; D013737:Testis / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C111047:SPAG9 protein, human; D054645:Protein Phosphatase 1