Vacuolar protein sorting-associated protein 28 homolog is a protein that in humans is encoded by the VPS28 gene. This gene encodes a protein involved in endosomal sorting of cell surface receptors via a multivesicular body/late endosome pathway. The encoded protein is one of the three subunits of the ESCRT-I complex (endosomal complexes required for transport) involved in the sorting of ubiquitinated protein. The two other subunits of ESCRT-I are vacuolar protein sorting 23 (VPS23), also known as tumor susceptibility gene 101 (TSG101), and vacuolar protein sorting 37 (VPS37). Two alternative transcripts encoding different isoforms have been described. Additional alternative transcripts may exist but the proteins encoded by these transcripts have not been verified experimentally. VPS28 has been shown to interact with TSG101.
Background References
1. Liu LL. et. al. Regulation of VPS28 gene knockdown on the milk fat synthesis in Chinese Holstein dairy. Yi Chuan. 2018 Dec.
2. Mezzofanti E. et. al. Vps28 Is Involved in the Intracellular Trafficking of Awd, the Drosophila Homolog of NME1/2. Front Physiol. 2019 Aug.
Western blot analysis of VPS28 on different lysates with Rabbit anti-VPS28 antibody (ET7110-94) at 1/2,000 dilution.
Lane 1: HepG2 cell lysate Lane 2: Jurkat cell lysate Lane 3: A549 cell lysate Lane 4: Mouse brain tissue lysate Lane 5: Rat brain tissue lysate
Lysates/proteins at 20 µg/Lane.
Predicted band size: 25 kDa Observed band size: 25 kDa
Exposure time: 3 minutes; ECL: K1801;
4-20% SDS-PAGE gel.
Proteins were transferred to a PVDF membrane and blocked with 5% NFDM/TBST for 1 hour at room temperature. The primary antibody (ET7110-94) at 1/2,000 dilution was used in 5% NFDM/TBST at 4℃ overnight. Goat Anti-Rabbit IgG - HRP Secondary Antibody (HA1001) at 1/50,000 dilution was used for 1 hour at room temperature.
Immunocytochemistry analysis of Jurkat cells labeling VPS28 with Rabbit anti-VPS28 antibody (ET7110-94) at 1/100 dilution.
Cells were fixed in 4% paraformaldehyde for 15 minutes at room temperature, permeabilized with 0.1% Triton X-100 in PBS for 15 minutes at room temperature, then blocked with 1% BSA in 10% negative goat serum for 1 hour at room temperature. Cells were then incubated with Rabbit anti-VPS28 antibody (ET7110-94) at 1/100 dilution in 1% BSA in PBST overnight at 4 ℃. Goat Anti-Rabbit IgG H&L (iFluor™ 488, HA1121) was used as the secondary antibody at 1/1,000 dilution. PBS instead of the primary antibody was used as the secondary antibody only control. Nuclear DNA was labelled in blue with DAPI.
Beta tubulin (HA601187, red) was stained at 1/100 dilution overnight at +4℃. Goat Anti-Mouse IgG H&L (iFluor™ 594, HA1126) was used as the secondary antibody at 1/1,000 dilution.
Flow cytometric analysis of Jurkat cells labeling VPS28.
Cells were fixed and permeabilized. Then stained with the primary antibody (ET7110-94, 1/1,000) (red) compared with Rabbit IgG Isotype Control (green). After incubation of the primary antibody at +4℃ for an hour, the cells were stained with a iFluor™ 488 conjugate-Goat anti-Rabbit IgG Secondary antibody (HA1121) at 1/1,000 dilution for 30 minutes at +4℃. Unlabelled sample was used as a control (cells without incubation with primary antibody; black).
VPS28 was immunoprecipitated from 0.2 mg Jurkat cell lysate with ET7110-94 at 2 µg/10 µl beads. Western blot was performed from the immunoprecipitate using ET7110-94 at 1/2,000 dilution. HRP Conjugated Anti-Rabbit IgG for IP Nano-secondary antibody at 1/5,000 dilution was used for 1 hour at room temperature.
Lane 1: Jurkat cell lysate (input) Lane 2: ET7110-94 IP in Jurkat cell lysate Lane 3: Rabbit IgG instead of ET7110-94 in Jurkat cell lysate