Related Experiment Video

Updated: Aug 5, 2026

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta
10:27

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta

Published on: December 5, 2019

Characterization of human hect domain family members and their interaction with UbcH5 and UbcH7

S E Schwarz1, J L Rosa, M Scheffner

  • 1Deutsches Krebsforschungszentrum, Angewandte Tumorvirologie, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany.

The Journal of Biological Chemistry
|June 20, 1998
PubMed

Insights

The hect domain protein family, including E3 ubiquitin ligases, forms thioester complexes with ubiquitin. These proteins exhibit distinct E2 specificities, classifying them into groups crucial for ubiquitin-dependent protein degradation.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Genetics

Background:

  • The hect domain protein family is defined by sequence similarity to E3 ubiquitin-protein ligase E6-AP.
  • E3 ubiquitin ligases are critical for protein ubiquitination and degradation pathways.
  • The C-terminal region of E6-AP is essential for ubiquitin thioester complex formation.

Purpose of the Study:

  • To investigate the role of the hect domain in ubiquitin thioester complex formation.
  • To determine the extent of the hect domain protein family in the human genome.
  • To explore the E2 specificity of human hect domain proteins.

Main Methods:

  • Sequence similarity analysis to identify hect domain proteins.
  • Biochemical assays to assess ubiquitin thioester adduct formation.
  • Interaction studies to determine E2 enzyme specificity (UbcH5 and UbcH7).

Main Results:

  • The hect domain of E6-AP is both necessary and sufficient for ubiquitin thioester adduct formation.
  • The human genome encodes at least 20 hect domain proteins.
  • Several hect domain proteins form thioester complexes with ubiquitin.
  • Human hect domain proteins can be classified into at least two groups based on preferential interaction with UbcH5 or UbcH7.

Conclusions:

  • Hect domain proteins constitute a family of E3 ubiquitin ligases.
  • The diversity in E2 specificity among hect domain proteins contributes to the specificity of ubiquitination.
  • A large family of E3 ligases ensures selectivity in ubiquitin-dependent proteolysis.

More Related Videos

Stability and Structure of Bat Major Histocompatibility Complex Class I with Heterologous β2-Microglobulin11:17

Stability and Structure of Bat Major Histocompatibility Complex Class I with Heterologous β2-Microglobulin

Published on: March 10, 2021

In Vitro Analysis of E3 Ubiquitin Ligase Function06:06

In Vitro Analysis of E3 Ubiquitin Ligase Function

Published on: May 14, 2021

Related Concept Videos

Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
Protein Complexes with Interchangeable Parts01:57

Protein Complexes with Interchangeable Parts

Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
The Nucleosome Core Particle02:10

The Nucleosome Core Particle

Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
The paradox
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their main responsibility is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. While on the other hand, they must allow polymerase enzymes to access DNA...
Position-effect Variegation02:32

Position-effect Variegation

In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
Heterochromatin02:38

Heterochromatin

The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at 9th...
The Nucleosome Core Particle01:12

The Nucleosome Core Particle

Nucleosomes are the DNA-histone complex, where the DNA strand is wound around the histone core. The histone core is an octamer containing two copies of H2A, H2B, H3, and H4 histone proteins.
Nucleosomes, paradoxically, perform two opposite functions simultaneously. On the one hand, their primary aim is to protect the delicate DNA strands from physical damage and help achieve a higher compaction ratio. On the other hand, they must allow polymerase enzymes to access histone-bound DNA during...