Related Experiment Video

Updated: Aug 9, 2026

Using an α-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking
11:57

Using an α-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking

Published on: March 28, 2014

Aspergillus niger G proteins: subcellular localization

X Mérit1, J Frot-Coutaz, R Got

  • 1Laboratoire de Biochimie des Membranes, Université Lyon I, Villeurbanne, France.

FEMS Microbiology Letters
|May 1, 1992
PubMed

Insights

Researchers identified G proteins in Aspergillus niger, differentiating between cytosolic and membrane-bound forms. These proteins were found in the plasma membrane and endoplasmic reticulum, aiding fungal cell function studies.

Area of Science:

  • Molecular Biology
  • Mycology
  • Cell Biology

Background:

  • The postmitochondrial fraction of Aspergillus niger exhibits significant GTPase activity and GTP binding.
  • Understanding the localization of GTP-binding proteins is crucial for elucidating cellular signaling pathways in fungi.

Purpose of the Study:

  • To characterize the subcellular localization of G proteins within Aspergillus niger.
  • To identify and differentiate between cytosolic and membrane-bound G protein populations.

Main Methods:

  • Subcellular fractionation using sucrose gradient centrifugation.
  • Isolation and iodination of outer proteins from Aspergillus niger protoplasts.
  • Immunological detection assays to identify G protein populations.

Main Results:

  • Separated a cytosolic and four membranous populations based on density.
  • Identified the fungal plasma membrane fraction, characterized by the absence of typical enzymes.
  • Detected cytosolic G proteins and small G proteins in plasma membrane and endoplasmic reticulum membranes using immunological methods.

Conclusions:

  • Successfully localized cytosolic and membrane-bound G proteins in Aspergillus niger.
  • Established the presence of these proteins in both the plasma membrane and endoplasmic reticulum.
  • Provided insights into the distribution of G proteins, contributing to fungal cell biology research.

More Related Videos

Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass13:08

Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass

Published on: August 10, 2017

Imaging ATG9A, a Multi-Spanning Membrane Protein07:20

Imaging ATG9A, a Multi-Spanning Membrane Protein

Published on: June 16, 2023

Related Concept Videos

G-protein Coupled Receptors01:21

G-protein Coupled Receptors

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
GTPases and their Regulation02:14

GTPases and their Regulation

Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒  small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Coat Assembly and GTPases01:33

Coat Assembly and GTPases

Vesicles incorporate different coat protein subunits in different cell locations, which changes the properties of the coat, such as the shape and geometry of the transport vesicles. Thus, vesicle coat proteins also play a significant role in cargo selection.
Coat assembly depends on the local availability of phosphatidylinositol phosphates or PIPs and GTP-binding proteins. Adaptor proteins, which link the coat proteins to the membrane, bind to these PIPs and play a crucial role in controlling...
G-protein Coupled Receptors01:21

G-protein Coupled Receptors

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.
GTPases and their Regulation02:14

GTPases and their Regulation

Guanine nucleotide-binding proteins (G-proteins), also known as GTPases, are a superfamily of proteins that regulate many cellular processes, such as cell signaling, vesicular transport, and the regulation of cell shape and motility. Mutation or dysfunction of these proteins can lead to disease. There are around 40,000 known G-proteins that can broadly be classified into two groups ‒  small G-proteins consisting of a single domain and large multi-domain G-proteins.
Large G-proteins, also known...
Activation and Inactivation of G Proteins01:22

Activation and Inactivation of G Proteins

Heterotrimeric G proteins are guanine nucleotide-binding proteins. As the name suggests, heterotrimeric G proteins are composed of three subunits: alpha, beta, and gamma. They remain GDP-bound or GTP-bound inside the cells and switch between inactive/active states. The Gα subunit possesses the nucleotide-binding pocket that binds guanine nucleotides and switches between GDP or GTP-bound states. In contrast, the Gꞵ and Gγ subunits are always bound together with high affinity and are together...