Stop or go: The cell maintains its fine motility balance with the help of tropomodulin

February 17, 2020

In a healthy cell, there is a fine balance between the protrusive structures that make the cell more migratory and the contractile structures that maintain the cell's shape and its association with the environment. A disturbance in this balance leads to several diseases, such as invasive cancers.

The most important component of both protrusive and contractile machineries is a protein called actin. This means that the proper distribution of actin between these structures is essential for the normal function of the cell. Nevertheless, the mechanisms that ensure that actin is distributed correctly between the protrusive and contractile machineries have remained elusive.

Researchers at the University of Helsinki, Finland, and the University of Pennsylvania, Philadelphia, USA, have now identified a protein called tropomodulin as a key player that maintains the balance between the protrusive and contractile actin-filament machineries within a cell.

The function of tropomodulin has previously been studied mainly in the context of muscles, where it maintains the architecture of actin filaments within the contractile fibers of muscle cells.

"We have now revealed that tropomodulins stabilise the actin filaments of the contractile structures in non-muscle cells through interacting with specific proteins within these actin filament bundles. The depletion of tropomodulins led to a loss of contractile structures, accompanied by an excess of protrusive structures, and thus to severe problems in a cell's shape and force production," says Academy Professor Pekka Lappalainen from the HiLiFE - Institute of Biotechnology, University of Helsinki.

Researchers were surprised to see that the depletion of one protein can have such drastic effects on the balance of the actin machinery.

"Another exciting and unexpected finding of this study was the notion that the same protein can have a different function depending on the tissue or cell type. Our study also sheds light on why abnormal levels of tropomodulin are linked to the progression of various cancers," says PhD student Reena Kumari.

University of Helsinki

Related Protein Articles from Brightsurf:

The protein dress of a neuron
New method marks proteins and reveals the receptors in which neurons are dressed

Memory protein
When UC Santa Barbara materials scientist Omar Saleh and graduate student Ian Morgan sought to understand the mechanical behaviors of disordered proteins in the lab, they expected that after being stretched, one particular model protein would snap back instantaneously, like a rubber band.

Diets high in protein, particularly plant protein, linked to lower risk of death
Diets high in protein, particularly plant protein, are associated with a lower risk of death from any cause, finds an analysis of the latest evidence published by The BMJ today.

A new understanding of protein movement
A team of UD engineers has uncovered the role of surface diffusion in protein transport, which could aid biopharmaceutical processing.

A new biotinylation enzyme for analyzing protein-protein interactions
Proteins play roles by interacting with various other proteins. Therefore, interaction analysis is an indispensable technique for studying the function of proteins.

Substituting the next-best protein
Children born with Duchenne muscular dystrophy have a mutation in the X-chromosome gene that would normally code for dystrophin, a protein that provides structural integrity to skeletal muscles.

A direct protein-to-protein binding couples cell survival to cell proliferation
The regulators of apoptosis watch over cell replication and the decision to enter the cell cycle.

A protein that controls inflammation
A study by the research team of Prof. Geert van Loo (VIB-UGent Center for Inflammation Research) has unraveled a critical molecular mechanism behind autoimmune and inflammatory diseases such as rheumatoid arthritis, Crohn's disease, and psoriasis.

Resurrecting ancient protein partners reveals origin of protein regulation
After reconstructing the ancient forms of two cellular proteins, scientists discovered the earliest known instance of a complex form of protein regulation.

Sensing protein wellbeing
The folding state of the proteins in live cells often reflect the cell's general health.

Read More: Protein News and Protein Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to