Disease relevance of SBP1

• Yeast SSB-1 was expressed in Escherichia coli cells by using a phage T7 expression system [1].

High impact information on SBP1

• A typical haploid cell contains about 20,000 molecules of SSB-1; thus, the cells can tolerate up to 60,000 copies [1].
• A yeast gene encoding SSB-1, a single-stranded nucleic acid binding protein, has been isolated by screening a lambda gt11 genomic DNA library [1].
• In this work, we identify Sbp1p (formerly known as Ssb1p), an abundant RNA binding protein, as a high-copy-number suppressor of a conditional allele in the decapping enzyme [2].
• In addition, Sbp1p promotes translational repression of mRNA during glucose deprivation [2].
• In mammalian cells, wild-type yeast, and rescued mutant yeast, exogenous full-length RanBP1 and sbp1p localized predominantly to the cytosol, whereas exogenous RBDs localized predominantly to the cell nucleus [3].

Biological context of SBP1

• The primary sequence of SBP1 indicates 22.5% identity with that of Vta1p from Saccharomyces cerevisiae, which was recently identified as a novel class E Vps protein binding to Vps4p [4].

Anatomical context of SBP1

• Antibodies to fibrillarin and SSB1 labelled coiled bodies strongly, though neither protein was detected in the nucleolar vacuoles [5].
• Endogenous SBP1 is exclusively localized to cytosol, however it is redirected to an aberrant endosomal structure, the E235Q compartment, in the cells expressing SKD1(E235Q) [4].

Analytical, diagnostic and therapeutic context of SBP1

• In situ labelling with probes to the snoRNAs U3 and U14, and immunofluorescence labelling with antibodies to fibrillarin and SSB1 showed a high degree of coincidence with the ETS pattern, confirming that ETS cleavage and 18 S rRNA production occur in the DFC [5].

References