RNA-binding protein involved in the histone pre-mRNA processing (PubMed:8957003, PubMed:9049306, PubMed:12588979, PubMed:19155325). Binds the stem-loop structure of replication-dependent histone pre-mRNAs and contributes to efficient 3'-end processing by stabilizing the complex between histone pre-mRNA and U7 small nuclear ribonucleoprotein (snRNP), via the histone downstream element (HDE) (PubMed:8957003, PubMed:9049306, PubMed:12588979, PubMed:19155325). Plays an important role in targeting mature histone mRNA from the nucleus to the cytoplasm and to the translation machinery (PubMed:8957003, PubMed:9049306, PubMed:12588979, PubMed:19155325). Stabilizes mature histone mRNA and could be involved in cell-cycle regulation of histone gene expression (PubMed:8957003, PubMed:9049306, PubMed:12588979, PubMed:19155325). Involved in the mechanism by which growing oocytes accumulate histone proteins that support early embryogenesis (By similarity). Binds to the 5' side of the stem-loop structure of histone pre-mRNAs (By similarity). Monomer (PubMed:22439849). SLBP/pre-mRNA complex interacts with ZNF473 (PubMed:11782445). Interacts with the Importin alpha/Importin beta receptor, LSM1, MIF4GD, TNPO3 and UPF1 (PubMed:15829567, PubMed:16086026, PubMed:18025107). Interaction with LSM1 occurs when histone mRNA is being rapidly degraded during the S phase (PubMed:18172165). Found in a ternary complex with ERI1 and the stem-loop structure of the 3' end of histone mRNA (PubMed:16912046). Associates with polyribosomes (PubMed:12588979). Identified in a histone pre-mRNA complex, at least composed of ERI1, LSM11, SLBP, SNRPB, SYNCRIP and YBX1 (By similarity). Binds in a cooperative manner with ERI1 to the mature 3'-end of histone mRNAs (By similarity). Polyribosome-associated (PubMed:12588979). Localizes predominantly in the nucleus at the G1/G2 phases and the beginning of S phase (PubMed:12588979). Through the S phase, partially redistributes to the cytoplasm (PubMed:12588979). Binding to histone mRNA is necessary for cytoplasmic localization (PubMed:12588979). Shuttles between the nucleus and the cytoplasm (PubMed:15829567). Imported in the nucleus by the Importin alpha/Importin beta receptor (PubMed:15829567). Widely expressed. Regulated during the cell cycle: protein levels increase 10 to 20 fold in the late G1 and decrease at the S/G2 border. Amino acids 31-34, 96-99 and 241-244 are necessary for interaction with the Importin alpha/Importin beta receptor. The first 18 amino acids, amino acids 69-76 and 179-182 are necessary for interaction with TNPO3. Amino acids 31-34, 96-99 and 241-244 are necessary for nuclear localization. Phosphorylated on Thr-61 and Thr-62 in the S-phase. Phosphorylation of Thr-62 by CDK1 primes phosphorylation of Thr-61 by CK2. Phosphorylation of Thr-62 is required for its degradation by the proteasome at the end of the S phase. Its degradation is not required for histone mRNA degradation at the end of the S phase. All the phosphorylated forms detected are present in the cytoplasm. Both unphosphorylated and phosphorylated forms bind the stem-loop structure of histone mRNAs. Phosphorylation at Thr-171 increases affinity for histone mRNAs. Ubiquitinated by the CRL2(FEM1A), CRL2(FEM1B) and CRL2(FEM1C) complexes, leading to its degradation. Belongs to the SLBP family.