High impact information on Pros28.1

• Integrins of the beta7 subfamily, alpha4 beta7 and alphaE beta7, contribute to lymphocyte homing and to the development of protective or autoreactive immune responses at mucosal sites [1].
• We have examined the functional role of the putative nuclear localization signal (NLS) -KKKQKK-in the Drosophila PROS-28.1 subunit by deletion mutagenesis and transfection experiments [2].
• Linkage of the putative PROS-28.1 NLS to BSA as reporter protein and in vitro import studies with permeabilized mouse NIH 3T3 cells show that this NLS is able to induce complete translocation of the reporter protein into the cell nucleus [2].
• Rapid evolution through gene duplication and subfunctionalization of the testes-specific alpha4 proteasome subunits in Drosophila [3].
• The Pros28.1B gene has two introns, located in exactly analogous positions as the two introns in Pros28.1, while the Pros28.1A gene lacks introns [4].

Biological context of Pros28.1

• The alpha4_dv gene maps to the X chromosome at 12A-C, its product shares 90% amino acid identity with alpha4_dm, and it is expressed at high levels in both males and females [5].
• The existence of testes-specific alpha4-type subunits in two widely diverged subgenera of Drosophila suggests that these subunit isoforms have important functional roles in spermatogenesis [5].
• Using the previously cloned proteasome alpha-type subunit gene Pros28.1, we screened a Drosophila melanogaster genomic library using reduced stringency conditions to identify closely related genes [4].
• In accordance with the nomenclature of proteasome subunits in Drosophila, the corresponding gene is designated PROS-28.1, and it encodes an mRNA of 1.1 kb with an open reading frame of 249 amino acids (aa) [6].
• In situ hybridization shows that the members of the PROS gene family are not organized in a single gene cluster and that, in contrast to the PROS-Dm35 gene, the PROS-Dm28.1 gene is localized on the X chromosome [7].

Anatomical context of Pros28.1

• As the LG4-LG5 domain of the alpha4 chain is cleaved in vivo from the main body of laminin-8 (alpha4beta1gamma1), we suggest that the heparan sulphate proteoglycan-binding activity of LG4 is significant in modulating the signalling of Wnt, Decapentaplegic and fibroblast growth factors [8].

Associations of Pros28.1 with chemical compounds

• The aa sequence comparison of the products of PROS-28.1 and PROS-35 with the C2 proteasome subunit of rat shows a strong sequence similarity between the different proteasome subunits [6].
• With the vertebrate alpha4 beta2 nAChR, AOX enhances imidacloprid potency but CYP3 A4 does not [9].

Other interactions of Pros28.1

• We isolated the D. virilis orthologs of the somatically expressed gene, alpha4_dm, and the testes-specific gene, alpha4t2_dm [5].
• The principal mammalian brain nicotinic acetylcholine receptors (nAChRs) are the alpha-bungarotoxin (alpha-BGT)-insensitive alpha 4 beta 2 and the alpha-BGT-sensitive alpha 7 subtypes assayed with radiolabeled nicotinoids and alpha-BGT, respectively [10].

Analytical, diagnostic and therapeutic context of Pros28.1

• Genomic Southern-blot hybridization shows PROS-28.1 to be a member of a family of related genes [6].

References