title: Descriptive Analysis of LAP1 Distribution and That of Associated Proteins throughout Spermatogenesis.
abstract: Spermatogenesis comprises highly complex differentiation processes. Nuclear envelope (NE) proteins have been associated with these processes, including lamins, lamina-associated polypeptide (LAP) 2 and the lamin B-receptor. LAP1 is an important NE protein whose function has not been fully elucidated, but several binding partners allow predicting putative LAP1 functions. To date, LAP1 had not been associated with spermatogenesis. In this study, LAP1 expression and cellular/subcellular localization during spermatogenesis in human and mouse testes is established for the first time. The fact that LAP1 is expressed during nuclear elongation in spermiogenesis and is located at the spermatids' centriolar pole is singularly important. LAP1 binds to members of the protein phosphatase 1 (PP1) family. Similar localization of LAP1 and PP1γ2, a testis-specific PP1 isoform, suggests a shared function for both proteins during spermiogenesis. Furthermore, this study suggests an involvement of LAP1 in manchette development and chromatin regulation possibly via interaction with acetylated α-tubulin and lamins, respectively. Taken together, the present results indicate that, by moving to the posterior pole in spermatids, LAP1 can contribute to the achievement of non-random, sperm-specific chromatin distribution, as well as modulate cellular remodeling during spermiogenesis. In addition, LAP1 seems to be associated with dynamic microtubule changes related to manchette formation and flagella development.
authors.affiliation: Neuroscience and Signaling Laboratory, Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal. jmbs@ua.pt.
authors.forename: Joana B
authors.initials: JB
authors.lastname: Serrano
authors.affiliation: Neuroscience and Signaling Laboratory, Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal. samartins@ua.pt.
authors.forename: Filipa
authors.initials: F
authors.lastname: Martins
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, 4710-057 Braga, Portugal. jcsousa@med.uminho.pt.|ICVS/3B's-PT Government Associate Laboratory, University of Minho, 4710-057 Braga/Guimarães, Portugal. jcsousa@med.uminho.pt.
authors.forename: João C
authors.initials: JC
authors.lastname: Sousa
authors.affiliation: Neuroscience and Signaling Laboratory, Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal. daniela.pereira@ua.pt.
authors.forename: Cátia D
authors.initials: CD
authors.lastname: Pereira
authors.affiliation: Center for Reproductive Medicine, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands. a.m.vanpelt@amc.uva.nl.
authors.forename: Ans M M
authors.initials: AM
authors.lastname: van Pelt
authors.affiliation: Neuroscience and Signaling Laboratory, Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal. srebelo@ua.pt.
authors.forename: Sandra
authors.initials: S
authors.lastname: Rebelo
authors.affiliation: Neuroscience and Signaling Laboratory, Department of Medical Sciences, Institute for Biomedicine-iBiMED, University of Aveiro, 3810-193 Aveiro, Portugal. odetecs@ua.pt.
authors.forename: Odete A B
authors.initials: OA
authors.lastname: da Cruz E Silva
keywords: lamina-associated polypeptide 1; lamins; manchette; nuclear envelope; protein phosphatase 1; spermatids