Homocysteine
Homocysteine, in the context of this target page, refers to the HERPUD1 gene product: the homocysteine-responsive endoplasmic reticulum-resident ubiquitin-like domain member 1 protein, also known as HERP, Mif1, SUP and KIAA0025. It is a component of the ER quality control system that supports degradation of misfolded ER proteins. Browse Assay Genie's current range of Homocysteine research reagents below, or read on for the biology behind the target.
The Homocysteine target page covers the protein encoded by HERPUD1, the homocysteine inducible ER protein with ubiquitin like domain 1. It is a component of the endoplasmic reticulum quality control (ERQC) system, also called ER-associated degradation (ERAD), which is involved in the ubiquitin-dependent degradation of misfolded ER proteins. It binds to ubiquilins, and this interaction is required for efficient degradation of CD3D through the ERAD pathway.
When unfolded proteins accumulate in the ER, the cell mounts an ER stress response. This includes inhibition of translation, increased expression of folding proteins (the unfolded protein response, UPR) and destruction of misfolded proteins by ERAD. The HERPUD1 gene may play a role in both UPR and ERAD. Its expression is induced by the UPR, and its promoter contains an ER stress response element. The encoded protein carries an N-terminal ubiquitin-like domain that may interact with the ERAD system, and it localises to the ER membrane. Alternative splicing produces multiple transcript variants encoding different isoforms, although the full-length nature of all variants has not been determined.
The protein has also been linked to presenilin biology. It has been shown to interact with presenilin proteins and to increase amyloid-beta protein levels when overexpressed, and it could enhance presenilin-mediated amyloid-beta 40 generation. Reflecting its history, previous names include homocysteine-inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1, and the symbol HERP. A mouse ortholog, Herpud1, is recognised.
Its expression is induced by the unfolded protein response and its promoter carries an ER stress response element, making it a useful readout of ER stress.
As an ERQC component, it supports ubiquitin-dependent degradation of misfolded ER proteins and works with ubiquilins in CD3D degradation.
Its N-terminal ubiquitin-like domain may interact with the ERAD system, supporting work on how misfolded proteins are recognised and cleared.
It interacts with presenilin proteins and increases amyloid-beta levels on overexpression, linking ER protein handling to amyloid-beta generation.
HERPUD1 encodes a component of the ER quality control, or ERAD, system that is involved in ubiquitin-dependent degradation of misfolded ER proteins. It binds ubiquilins, which is required for efficient degradation of CD3D, and it may play a role in both the UPR and ERAD.
Aliases include KIAA0025, Mif1, HERP and SUP, plus the intronic transcript symbol HERPUD1-IT1. Alternative splicing produces multiple transcript variants encoding different isoforms, although the full-length nature of all variants has not been determined.
A mouse ortholog, Herpud1, exists; check the datasheet of any product for its validated reactivity. The protein interacts with presenilin proteins and raises amyloid-beta levels when overexpressed, which connects it to amyloid-beta generation research.
Ubiquilins, presenilins, ERAD substrates and other ER stress and amyloid-beta pathway targets.
Gene and protein annotations from HGNC, NCBI Gene and UniProt Q15011; product specifications from Assay Genie datasheets.