Orb2

Required in mushroom body gamma neurons for long-term memory in male courtship. Binds to mRNA 3'-UTRs. In its monomeric form, acts as a translational repressor of genes involved in neuronal growth, synapse formation and protein turnover. In its amyloid-like oligomeric form, acts as a translational activator. The monomeric form reduces poly(A) tail length and destabilizes mRNA while the oligomeric form protects and elongates the poly(A) tail and stabilizes mRNA. Isoform A is required for initial memory acquisition and, following subsequent late dopaminergic pathway activation, isoform A recruits isoform B into a complex to activate translation of CaMKII which is required for long-term memory consolidation. Involved in asymmetric cell division in the central nervous system. Required for the progression of spermatogenesis through meiosis and for sperm differentiation. During sperm differentiation, required to asymmetrically localize and activate the translation of protein kinase aPKC mRNAs which is necessary for spermatid cyst polarization. Also required during spermatid cyst polarization for localization and translation of its own mRNA.

Full Name

oo18 RNA-binding protein2

Function

RNA-binding protein involved in translational regulation and required for long-term memory (PubMed:28525754, PubMed:29105522).
Required in mushroom body gamma neurons for long-term memory in male courtship (PubMed:17965711, PubMed:23083740).
Binds to mRNA 3'-UTRs (PubMed:20547833, PubMed:26638074, PubMed:24830287, PubMed:26095367, PubMed:32165583).
In its monomeric form, acts as a translational repressor of genes involved in neuronal growth, synapse formation and protein turnover (PubMed:20547833, PubMed:26638074, PubMed:32165583).
In its amyloid-like oligomeric form, acts as a translational activator (PubMed:26638074, PubMed:32165583).
The monomeric form reduces poly(A) tail length and destabilizes mRNA while the oligomeric form protects and elongates the poly(A) tail and stabilizes mRNA (PubMed:26638074).
Involved in asymmetric cell division in the central nervous system (PubMed:21900268).
Plays a role in synapse formation and morphology at neuromuscular junctions by modulating the translation of the tumor suppressor brat (PubMed:29105522).
Required for the progression of spermatogenesis through meiosis and for sperm differentiation (PubMed:23209437).
During sperm differentiation, required to asymmetrically localize and activate the translation of protein kinase aPKC mRNAs which is necessary for spermatid cyst polarization (PubMed:24830287).
Also required during spermatid cyst polarization for localization and translation of its own mRNA (PubMed:24830287).
Isoform A
Required for initial memory acquisition (PubMed:26095367, PubMed:28525754).
Following subsequent late dopaminergic pathway activation, recruits isoform B into a complex to activate translation of CaMKII which is required for long-term memory consolidation (PubMed:26095367).

Biological Process

Asymmetric cell divisionManual Assertion Based On ExperimentIMP:FlyBase
Long-term memoryManual Assertion Based On ExperimentIMP:UniProtKB
Male courtship behaviorManual Assertion Based On ExperimentIMP:FlyBase
Male meiosis IManual Assertion Based On ExperimentIMP:FlyBase
Negative regulation of cytoplasmic translationManual Assertion Based On ExperimentIBA:GO_Central
Negative regulation of translationManual Assertion Based On ExperimentIDA:FlyBase
Positive regulation of translationManual Assertion Based On ExperimentIDA:FlyBase
Protein stabilizationManual Assertion Based On ExperimentIDA:UniProtKB
Sperm axoneme assemblyManual Assertion Based On ExperimentIMP:FlyBase
Sperm individualizationManual Assertion Based On ExperimentIMP:FlyBase
SpermatogenesisManual Assertion Based On ExperimentIMP:FlyBase

Cellular Location

Perikaryon
Cell projection, axon
Cell projection, dendrite
Cell junction, synapse
Cytoplasm
Cytoplasm, perinuclear region
In embryonic and larval nervous system, concentrated in the perikaryon (PubMed:21900268).
In the adult central nervous system, localizes to synaptic terminals (PubMed:21900268).
In the ovary, localizes to the cytoplasm of nurse cells (PubMed:21900268).
Localizes to neuromuscular junctions (PubMed:29105522).
In spermatocytes, localizes throughout the cytoplasm with higher levels concentrated in a ring around the nucleus (PubMed:23209437).
The oligomeric form is enriched in the synaptic region (PubMed:22284910).
Isoform A
Cell junction, synapse
Isoform B
Perikaryon
Cell projection, axon
Cell junction, synapse

PTM

Phosphorylation regulates interaction with Tob and oligomerization. Protein phosphatase 2A keeps both Orb2 and Tob in an unphosphorylated form. Following synaptic activation, unphosphorylated Orb2 is bound and stabilized by unphosphorylated Tob. Tob recruits activated LimK which phosphorylates both Orb2 and Tob and enhances Orb2 oligomerization.