Disease relevance of SMP3

• Therefore, four Saps that are known to be expressed in C. albicans, Sap1, Sap2, Sap3 and Sap6, were produced in Escherichia coli as recombinant zymogens and purified in large quantities [1].
• Monoclonal antibody, LAS-2, directed against the alpha subunit of transducin (Gt alpha), inhibited Gt beta gamma-dependent, pertussis toxin-catalyzed ADP ribosylation of Gt alpha and was specific for Gt alpha [2].

High impact information on SMP3

• Human Smp3p adds a fourth mannose to yeast and human glycosylphosphatidylinositol precursors in vivo [3].
• The Smp3 protein, which is encoded by an essential gene, is therefore required for addition of the fourth Man to yeast GPI precursors [4].
• The ability to normally process Sap2 and form hyphae was restored upon transformation of null mutants with a KEX2-containing plasmid [5].
• Expression of SAP5 was observed only during infection with the Deltasap1/3 mutant, whereas upregulation of SAP2 and SAP8 transcripts was observed in the Deltasap1 and the Deltasap1/3 mutants [6].
• These results demonstrate that Sap2p is responsible for proteolysis of mucin by C. albicans in vitro and may be involved as a virulence factor in the breakdown of mucus and penetration of the mucin barrier by C. albicans [7].

Biological context of SMP3

• A new protein kinase, SSP31, modulating the SMP3 gene-product involved in plasmid maintenance in Saccharomyces cerevisiae [8].
• However, it did not suppress the phenotypes of stable maintenance of pSR1 and slow cell growth of the smp3 mutant, even when ligated into the multicopy vector, YEp24 [8].
• The pleiotropic smp3 mutation on the Saccharomyces cerevisiae chromosome confers three phenotypes, (i) stable maintenance of a heterologous plasmid pSR1 isolated from Zygosaccharomyces rouxii, (ii) slow cell growth, and (iii) temperature-sensitive growth [8].
• Deficiencies in the essential Smp3 mannosyltransferase block glycosylphosphatidylinositol assembly and lead to defects in growth and cell wall biogenesis in Candida albicans [9].

Associations of SMP3 with chemical compounds

• The essential Smp3 protein is required for addition of the side-branching fourth mannose during assembly of yeast glycosylphosphatidylinositols [4].

Regulatory relationships of SMP3

• The SSP31 gene of S. cerevisiae was isolated as a chromosomal DNA fragment suppressing the thermosensitive cell growth of the smp3 mutant when it was ligated into the low-copy vector, YCp50 [8].

Other interactions of SMP3

• A DNA fragment bearing the SMP2 gene was cloned by its ability to complement the slow growth of the smp2 smp3 double mutant (smp3 is another mutation conferring increased stability of plasmid pSR1) [10].
• CaSMP3 complements the inviable S. cerevisiae smp3 null mutant and, when expressed in an S. cerevisiae smp3/gpi13 double mutant, it permits in vivo conversion of the Man3-GPI precursor that accumulates in that mutant to a Man4-GPI [9].

Analytical, diagnostic and therapeutic context of SMP3

• SAP2 and SAP8 RT-PCR products were first detected 60 h after infection, while SAP4 and SAP5 transcripts were never discovered [11].
• In both media, only S. cerevisiae transformants harbouring SAP2 secreted the enzyme, as confirmed by proteinase activity assays and immunoblotting [12].
• The coding region of SAP2, including its signal sequence and propeptide, was amplified by PCR and cloned downstream of the S. cerevisiae or C. albicans ADH1 promoter [12].

References