ID Q9NPE6; PN Sperm-associated antigen 4 protein; GN SPAG4; OS 9606; SL Nucleus Position: SL-0178; SL Nucleus Position: SL-0179; SL Nucleus Position: SL-0182; SL Comments: Membrane {ECO:0000305}; Multi-pass membrane protein {ECO:0000305}. Cytoplasm, cytoskeleton {ECO:0000250|UniProtKB:O55034}. Cytoplasm, cytoskeleton, flagellum axoneme {ECO:0000250|UniProtKB:O55034}. Nucleus envelope {ECO:0000250|UniProtKB:Q9JJF2}. Nucleus inner membrane {ECO:0000250|UniProtKB:Q9JJF2}. Note=In spermatids, it is localized in the transient manchette and in the axoneme of elongating spermatids and epididymal sperm (By similarity). Colocalized with SEPT12 at the nuclear periphery in round spermatids, at sperm neck in elongated spermatids and at midpiece regions in ejaculated spermatozoa (PubMed:25775403). {ECO:0000250|UniProtKB:O55034, ECO:0000269|PubMed:25775403}. DR UNIPROT: Q9NPE6; DR UNIPROT: O43648; DR Pfam: PF07738; DR PROSITE: PS51469; DR OMIM: 603038; DR DisGeNET: 6676; DE Function: Involved in spermatogenesis. Required for sperm head formation but not required to establish and maintain general polarity of the sperm head. Required for anchoring and organization of the manchette. Required for targeting of SUN3 and probably SYNE1 through a probable SUN1:SYNE3 LINC complex to the nuclear envelope and involved in accurate posterior sperm head localization of the complex. May anchor SUN3 the nuclear envelope. Involved in maintenance of the nuclear envelope integrity. May assist the organization and assembly of outer dense fibers (ODFs), a specific structure of the sperm tail. {ECO:0000250|UniProtKB:O55034, ECO:0000250|UniProtKB:Q9JJF2}. DE Reference Proteome: Yes; DE Interaction: Q8IXM6; IntAct: EBI-24640159; Score: 0.56 DE Interaction: Q8TC36; IntAct: EBI-24639374; Score: 0.56 DE Interaction: Q9BXJ8; IntAct: EBI-22744045; Score: 0.56 DE Interaction: Q9H2S6; IntAct: EBI-24572530; Score: 0.56 DE Interaction: Q8IYM1; IntAct: EBI-10819487; Score: 0.61 DE Interaction: O95870; IntAct: EBI-24265964; Score: 0.56 DE Interaction: Q9H2L4; IntAct: EBI-24266054; Score: 0.56 DE Interaction: Q6UX98; IntAct: EBI-22746269; Score: 0.56 DE Interaction: Q8IWU4; IntAct: EBI-22747198; Score: 0.56 DE Interaction: P0DJD7; IntAct: EBI-24267883; Score: 0.56 DE Interaction: P78329; IntAct: EBI-22747716; Score: 0.56 DE Interaction: O14653; IntAct: EBI-24510927; Score: 0.56 DE Interaction: P07306; IntAct: EBI-24514111; Score: 0.56 DE Interaction: P24593; IntAct: EBI-24520110; Score: 0.56 DE Interaction: Q5TGU0; IntAct: EBI-24524123; Score: 0.56 DE Interaction: Q5J8X5; IntAct: EBI-24529588; Score: 0.56 DE Interaction: Q96GQ5; IntAct: EBI-24610016; Score: 0.56 DE Interaction: O00767; IntAct: EBI-24626536; Score: 0.56 DE Interaction: Q14656; IntAct: EBI-24535767; Score: 0.56 DE Interaction: P43378; IntAct: EBI-24536184; Score: 0.56 DE Interaction: Q96IW7; IntAct: EBI-24547117; Score: 0.56 DE Interaction: O95393; IntAct: EBI-24551734; Score: 0.56 DE Interaction: Q969E2; IntAct: EBI-24579620; Score: 0.56 DE Interaction: Q8TDX6; IntAct: EBI-24580321; Score: 0.56 DE Interaction: Q7Z2K6; IntAct: EBI-24591721; Score: 0.56 DE Interaction: P26678; IntAct: EBI-24597706; Score: 0.56 DE Interaction: A5PKU2; IntAct: EBI-24637775; Score: 0.56 GO GO:0005737; GO GO:0005856; GO GO:0005639; GO GO:0034993; GO GO:0031514; GO GO:0005635; GO GO:0043495; GO GO:0005198; GO GO:0030154; GO GO:0006998; GO GO:0007283; TP Membrane Topology: Transmembrane; Source: UniProt - Sequence Analysis {ECO:0000255}; SQ MRRSSRPGSASSSRKHTPNFFSENSSMSITSEDSKGLRSAEPGPGEPEGRRARGPSCGEPALSAGVPGGTTWAGSSQQKP SQ APRSHNWQTACGAATVRGGASEPTGSPVVSEEPLDLLPTLDLRQEMPPPRVFKSFLSLLFQGLSVLLSLAGDVLVSMYRE SQ VCSIRFLFTAVSLLSLFLSAFWLGLLYLVSPLENEPKEMLTLSEYHERVRSQGQQLQQLQAELDKLHKEVSTVRAANSER SQ VAKLVFQRLNEDFVRKPDYALSSVGASIDLQKTSHDYADRNTAYFWNRFSFWNYARPPTVILEPHVFPGNCWAFEGDQGQ SQ VVIQLPGRVQLSDITLQHPPPSVEHTGGANSAPRDFAVFGLQVYDETEVSLGKFTFDVEKSEIQTFHLQNDPPAAFPKVK SQ IQILSNWGHPRFTCLYRVRAHGVRTSEGAEGSAQGPH //