VPS28 SUBUNIT OF ESCRT-I; VPS28

Alternative titles; symbols

• VACUOLAR PROTEIN SORTING 28, YEAST, HOMOLOG OF

HGNC Approved Gene Symbol: VPS28

Cytogenetic location: 8q24.3 Genomic coordinates (GRCh38): 8:144,423,616-144,428,547 (from NCBI)

▼ Description
Class E vacuolar protein sorting (VPS) proteins, such as VPS28, are required for appropriate sorting of receptors within the endocytic pathway (Bishop and Woodman, 2001).

▼ Cloning and Expression
By searching EST databases for homologs of yeast Vps28, Bishop and Woodman (2001) identified human VPS28 and several invertebrate homologs. The 221-amino acid human protein shares 28% amino acid identity with yeast Vps28. RT-PCR analysis revealed ubiquitous expression of a single VPS28 transcript in human tissues. Immunofluorescence and confocal microscopy showed that VPS28 was exclusively cytosolic.

▼ Gene Function
Using coimmunoprecipitation and crosslinking analysis, Bishop and Woodman (2001) found that human VPS28 interacted with the coiled-coil C-terminal portion of TSG101 (601387). Expression of ATPase-defective VPS4 (609983) shifted a portion of TSG101 and VPS28 from the cytosol to endosomal vacuoles. Bishop and Woodman (2001) concluded that TSG101 and VPS28 are directly involved in endosomal sorting.

Philips et al. (2008) showed that the avirulent Mycobacterium smegmatis species could multiply in Drosophila S2 cells or murine macrophages in which small interfering RNA had disrupted components of the ESCRT (endosomal sorting complex required for transport) complex, including Tsg101 and Vps28, by modulating the phagosome induced by mycobacteria. Immunofluorescence and confocal microscopy showed that Tsg101- or Vps28-depleted cells harbored mycobacteria in a heavily ubiquitinated vacuolar location. Philips et al. (2008) concluded that ESCRT machinery is critical for containment of mycobacterial proliferation.

▼ Mapping
Gross (2018) mapped the VPS28 gene to chromosome 8q24.3 based on an alignment of the VPS28 sequence (GenBank BC006485) with the genomic sequence (GRCh38).