Related Experiment Video

Updated: Aug 8, 2026

Identification of Post-translational Modifications of Plant Protein Complexes
10:07

Identification of Post-translational Modifications of Plant Protein Complexes

Published on: February 22, 2014

Processing of p60v-src to its myristylated membrane-bound form

E A Garber, F R Cross, H Hanafusa

    Molecular and Cellular Biology
    |October 1, 1985
    PubMed

    Insights

    Myristoylation of Rous sarcoma virus p60src protein is crucial for its membrane association and cell transformation. This lipid modification occurs before membrane binding and is required for stable plasma membrane association.

    Area of Science:

    • Molecular Biology
    • Virology
    • Cell Biology

    Background:

    • p60src protein from Rous sarcoma virus is myristoylated at its N-terminal glycine residue.
    • Myristoylation is essential for p60src membrane association and cell transformation.
    • Previous studies utilized src mutants with alterations in the N-terminal 30 kilodaltons.

    Purpose of the Study:

    • To analyze the process of p60src myristoylation in wild-type and mutant-infected cells.
    • To investigate the relationship between initiator methionine removal and myristoylation.
    • To determine the role of myristoylation in p60src membrane association and interaction with cellular proteins.

    Main Methods:

    • Analysis of myristoylated src proteins in wild-type and mutant Rous sarcoma virus-infected cells.
    • Kinetics studies of myristoylation and p60src association with p50 and p90 proteins.
    • Examination of src mutants with specific deletions (e.g., amino acids 169-264) and N-terminal deletions.

    Main Results:

    • Removal of the initiator methionine is not obligatorily coupled with myristoylation.
    • Myristoylation precedes membrane association of p60src.
    • Transient association with p50 and p90 occurs independently of myristoylation.
    • Myristoylation is necessary but not sufficient for stable plasma membrane association.
    • A specific src deletion mutant (169-264) is myristoylated, membrane-unbound, transformation-defective, and stably associated with p50/p90.
    • N-terminal deletion mutants with tyrosine kinase activity can be myristoylated and membrane-bound but show reduced transformation activity.

    Conclusions:

    • Myristoylation is a critical step for p60src membrane localization and function.
    • Additional N-terminal domains beyond the myristoylation site are involved in full cell transformation.
    • The N-terminal region of p60src contains multiple functional domains regulating its activity and localization.

    More Related Videos

    Imaging Plasma Membrane Deformations With pTIRFM12:28

    Imaging Plasma Membrane Deformations With pTIRFM

    Published on: April 2, 2014

    Small-Scale Plasma Membrane Preparation for the Analysis of Candida albicans Cdr1-mGFPHis09:44

    Small-Scale Plasma Membrane Preparation for the Analysis of Candida albicans Cdr1-mGFPHis

    Published on: June 13, 2021

    Related Concept Videos

    Mitochondrial Precursor Proteins01:39

    Mitochondrial Precursor Proteins

    Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
    Most of the mitochondrial precursors...
    Translocation of Proteins into the Mitochondria01:19

    Translocation of Proteins into the Mitochondria

    Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
    Sorting of outer membrane proteins:
    Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
    Directing Proteins to the Rough Endoplasmic Reticulum01:34

    Directing Proteins to the Rough Endoplasmic Reticulum

    The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
    GPI Anchoring of Proteins in the ER Membrane01:29

    GPI Anchoring of Proteins in the ER Membrane

    GPI-anchoring is a post-translational, reversible protein modification that is ubiquitous in eukaryotes. Such proteins are primarily present on the exoplasmic leaflet of the plasma membrane.
    GPI-anchor structure
    A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
    Post-translational Translocation of Proteins to the RER01:27

    Post-translational Translocation of Proteins to the RER

    A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
    Targeting proteins to the ER
    Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
    Export of Misfolded Proteins out of the ER01:32

    Export of Misfolded Proteins out of the ER

    After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...