Protein: Survival motor neuron protein (Q9VV74)
Organism: Drosophila melanogaster (Fruit fly)
Function: The SMN complex plays an essential role in spliceosomal snRNP assembly in the cytoplasm, is required for pre-mRNA splicing in the nucleus and acts as a chaperone that discriminates target and non-target RNAs of Sm proteins. Required for normal expression of spliceosomal snRNAs and for U12 intron splicing. Required in cholinergic neurons, but not in motor neurons, to ensure correct splicing and proper levels of stas mRNA and normal neurotransmitter release by motor neurons. However, Smn is required in motor neurons, but not in cholinergic neurons, for normal motor behavior but plays no role in synaptic transmission according to a report. In both muscle and neurons, required for the formation of a normal neuromuscular junction (NMJ) structure. Plays a neuron-specific role in long-term homeostatic compensation at the larval NMJ. In the thorax of adult flies, required for Act88F, an indirect flight muscle (IFM)-specific actin, expression and for proper IFM myofibril formation. In nurse cells, oocytes and follicle cells, required to maintain normal organization of nuclear compartments including chromosomes, nucleoli, Cajal bodies, histone locus bodies and heterochromatin. Required for the functional integrity of the cytoplasmic U snRNP body (U body) and P body. Required in dividing postembryonic neuroblasts (pNBs) for the correct basal localization of mira. The tight regulation of its expression is critical for stem cell division, proliferation and differentiation in male germline and developing central nervous system (CNS). Required for tracheal terminal cell lumen formation.
Subcellular location: Cytoplasm {ECO:0000269|PubMed:16533947, ECO:0000269|PubMed:17353360, ECO:0000269|PubMed:17595295, ECO:0000269|PubMed:18791638, ECO:0000269|PubMed:18923150, ECO:0000269|PubMed:19464282, ECO:0000269|PubMed:20452345, ECO:0000269|PubMed:21490958, ECO:0000269|PubMed:21627586}. Nucleus {ECO:0000269|PubMed:18923150, ECO:0000269|PubMed:21627586}. Cytoplasm, U-body {ECO:0000269|PubMed:17595295, ECO:0000269|PubMed:19464282}. Nucleus, gem {ECO:0000269|PubMed:16533947, ECO:0000269|PubMed:17353360, ECO:0000269|PubMed:17595295, ECO:0000269|PubMed:18791638, ECO:0000269|PubMed:19464282, ECO:0000269|PubMed:20452345, ECO:0000269|PubMed:21490958, ECO:0000269|PubMed:21627586}. Nucleus, Cajal body {ECO:0000269|PubMed:18923150}. Cytoplasm, myofibril, sarcomere, I band {ECO:0000269|PubMed:16533947, ECO:0000269|PubMed:17353360, ECO:0000269|PubMed:17595295, ECO:0000269|PubMed:18791638, ECO:0000269|PubMed:19464282, ECO:0000269|PubMed:20452345, ECO:0000269|PubMed:21490958}. Cytoplasm, myofibril, sarcomere, Z line {ECO:0000269|PubMed:16533947, ECO:0000269|PubMed:17353360, ECO:0000269|PubMed:17595295, ECO:0000269|PubMed:18791638, ECO:0000269|PubMed:19464282, ECO:0000269|PubMed:20452345, ECO:0000269|PubMed:21490958}. Note=High expression detected in the cytoplasm of female germline stem cells and cystoblast which persists up to stage 10 egg chambers. Accumulates in the cytoplasm of dividing pNBs. Colocalizes with Actn at the Z-line of IFMs. Expression concentrates at the post-synaptic region of NMJs in larval brain. Component of nuclear gem (Gemini of Cajal bodies) structures that partially colocalize with or closely appose Cajal bodies (PubMed:21627586). {ECO:0000269|PubMed:16533947, ECO:0000269|PubMed:17353360, ECO:0000269|PubMed:17595295, ECO:0000269|PubMed:18791638, ECO:0000269|PubMed:19464282, ECO:0000269|PubMed:20452345, ECO:0000269|PubMed:21490958, ECO:0000269|PubMed:21627586}.
Interaction partners:
- Gem-associated protein 2
- RNA helicase
- Probable small nuclear ribonucleoprotein Sm D1
- Probable small nuclear ribonucleoprotein Sm D2
- Lsm10
- Gem-associated protein 5
- Gem-associated protein 4a
- Methylosome subunit pICln
- FI05704p
- Probable small nuclear ribonucleoprotein G
Sequence:
MSDETNAAVWDDSLLVKTYDESVGLAREALARRLADSTNKREEENAAAAEEEAGEISATGGATSPEPVSFKVGDYARATYVDGVDYEGAVVSINEEKGTCVLRYLGYENEQEVLLVDLLPSWGKRVRREQFLIAKKDEDEQLSRPKASAGSHSKTPKSSRRSRISGGLVMPPMPPVPPMIVGQGDGAEQDFVAMLTAWYMSGYYTGLYQGKKEASTTSGKKKTPKK