Protein: Protein cup (Oskar ribonucleoprotein complex 147 kDa subunit) (Q9VMA3)
Organism: Drosophila melanogaster (Fruit fly)
Function: Adapter protein that plays a central role in localization of transcripts in the oocyte and in young embryos. Maintains RNA targets in a repressed state by promoting their deadenylation and protects deadenylated mRNAs from further degradation. Binds to and recruits eIF-4E to the 3'-UTR of some mRNA targets which prevents interaction between eIF4E1 and eIF4G. This may contribute to translational repression but does not appear to be necessary for it to occur. Can promote translational repression independently of deadenylation and eIF4E1 binding. Required for correct localization of eIF4E1 in the developing oocyte. Required for translational repression of oskar (osk) mRNA. Also required for the translational repression of nanos (nos) mRNA. Promotes the accumulation of the germ plasm components osk, vas and stau at the posterior pole of the oocyte and is required for germ cell development. Represses orb positive autoregulatory activity which prevents premature activation of orb and ensures its accumulation specifically in the developing oocyte. In 0-1 hour embryos, forms a complex with me31B, cup, tral and pAbp which binds to various mRNAs including maternal mRNAs, and down-regulates their expression during the maternal-to-zygotic transition.
Subcellular location: Cytoplasm {ECO:0000269|PubMed:15465908, ECO:0000269|PubMed:17277377, ECO:0000269|PubMed:24335285, ECO:0000269|PubMed:9118812}. Nucleus {ECO:0000269|PubMed:15465908, ECO:0000269|PubMed:24335285}. Cytoplasm, Cytoplasmic ribonucleoprotein granule {ECO:0000269|PubMed:17178403}. Note=Retained in the cytoplasm by interaction with eIF4E1. Located throughout the cytoplasm of all germline cells and is excluded from the nucleus of nurse cells, oocytes and follicular cells (PubMed:15465908). During oogenesis, accumulates in the cytoplasm at the posterior end of the forming oocyte (PubMed:15465908). Component of the germ plasm in developing oocytes (PubMed:22454519). Does not localize in processing bodies (P-bodies) (PubMed:24335285). {ECO:0000269|PubMed:15465908, ECO:0000269|PubMed:22454519, ECO:0000269|PubMed:24335285}.
Interaction partners:
- Eukaryotic translation initiation factor 4E1
- ATP-dependent RNA helicase me31b
- Trailer hitch, isoform H
- FI20148p1
- LD37574p
- Protein nanos
- eIF-4F 25 kDa subunit
- eIF-4F 25 kDa subunit
- eIF-4F 25 kDa subunit
- eIF-4F 25 kDa subunit
Sequence:
MQMAEAEQENGAGALKIATNAGATDRPAHQQLPLPVEDQQDEVLTPAEKGKFEYPPPPPPPTPVQAPLATKATALNASQEHDDDEANSEKWEDPCAPPPPPPLPTSAFLATGLGYLKLPAFKLKDALEKAITKLEANKRTLKASPESSRSIKNKNVVALEMLPRRSNPETIGDGSMLASTSTAVMLQTKKPAVIVEMERRCKIINLLAKQNQILESISGEAIPMHGPSKHLHEDEGLTLQVLSARASTPYTQPSSMLSCTAVSCDLEHDSPRKQVASKEAVPEQQSSQVQQKRPPSTGIHKPGSLRAPKAVRPTTAPVVSSKPVKSYTRSRLMDIRNGMFNALMHRSKESFVMPRIATCDDIELEGRLRRMNIWRTSDGTRFRTRSTTANLNMNNNNNNECMPAFFKNKNKPNLISDESIIQSQPPQPQTEFQDPAIVNQRRIGSGRLNHSKWGYNDEDYHSYHNGKSQHMEEVNSKNSKNMTVLQFFDNGEISSQPQRRPNTPVMGMSINRSENDTLHSNESSEDLSRANENYVKRVMSGFLVVSKPKSRDVEDRHHRRYRNQNEEPEWFSCGPTSRLDTIELCGFDEDEEKMLKEGNKNHGLGETERETSKQKMDHKYKWTHAEPMGRSKYMPKHDTNNNHNVENMNNVMATEHQQQKEEKRPGSGRSFQFDKFNQSQQNYESSSYVNHQQPPQTQPQQMQQQSNTNTNNSKFMSFFANEGNSSSSSLNEFFKQAINQGHGNNPEQPKSLGHIGQMPSVDQLEAKWRRNSLNNVGETANKQTDNFQKLIGSLSSAKPQSQAVGYDAISNFIMQQQQYQQQQQKQHLIIQQQQQHTAFLASLQLKAILGRADTQLLLLRLTKGEISKHGLLVQLANPRLTDMDREAITAVLQFTNTQQQQQQHKQQLDMLSSTVIASQLQNLHNLAIVQQTLAARQQPQHNPQTQAPHQLSQEDLQAHANVIMRNAVMKRKIEEQTSKLINGGAKHQAQQQYLNRGQQRQARPDANSNALLHALISGGGNNHASGYPMNGQPQKHHSNLRFGDNQNFQSFESNQPHFATQYKQQYQQSQQQHPHQQPQQLNSLHQNNAGAVNSFNKAQMQAQSAISMLPNSGDEFH