Competing proteins

[MarkE]

Are proteins in our body competition with each other? It is known that bacteria in our intestines compete, but regarding proteins I only found here:

 

"RNA transcripts, both protein-coding and non-coding, thus have the ability to compete for microRNA binding and co-regulate each other in complex ceRNA networks (ceRNETs)"

 

Does anyone know more competition in our body?

[CharonY]

Competing in what context? Substrate? Sure, different proteins can bind to the same substrate. But this is not analogous to bacterial competition.

[MarkE]

You mean, CharonY, that bacterial competition is different to protein competition because proteins won't 'actively' try to get to the site, whereas bacteria do? That is an understandable way of looking at it, but I think it's still considered competetion, because you're able to be in competition in a passive way, f.i. in the supermarket soft drinks like Coca Cola, Sprite, Fanta etc. are in competition with each other, because one of them is going to be bought. In this case the person in the supermarket is active here, she's going to choose one drink. How about the sites where proteins are being taken up, are they active? Ir is it proven they are entirely passive? Also, the drinks aren't that passive, because words like 'less sugar' of 'buy 3, pay 2' are influenzing the buyer' to choose the product.

 

In terms of human fertilization I read here the following:
"Female factors can influence the result of sperm competition through a process known as "sperm choice". Proteins present in the female reproductive tract or on the surface of the ovum may influence which sperm succeeds in fertilizing the egg. During sperm choice females are able to discriminate and differentially use the sperm from different males. One instance where this is known to occur is inbreeding; females will preferentially use the sperm from a more distantly related male than a close relative".

 

In fish (in this case salmon and trout) it seems to me (I read here) that the females are even more active:

"We found that activating sperm in ovarian fluid makes them live about twice as long as in river water. Importantly, both species' sperm also switch from swimming in tight elliptical circles in river water, to swimming in straightened trajectories in ovarian fluid. This behaviour allows sperm to navigate towards the egg by following a chemical cue".

I'd like to know if proteins are, in the same way as these examples, in competition which each other.

Edited January 21, 2015 by MarkE

[CharonY]

It is a matter of scale. When we talk about competition between organisms (and cells) mechanisms and principles are different from the molecular scale. To use the same term to compare those to is bound to obfuscate matter.

 

For example, protein actions are guided by thermodynamic interaction. Biological systems, such as cells, react to stimuli and produce answers, including production of proteins.

[Aminoxyl]

"RNA transcripts, both protein-coding and non-coding, thus have the ability to compete for microRNA binding and co-regulate each other in complex ceRNA networks (ceRNETs)"

 

 

This quote refers not to proteins but to RNA transcripts. It is stating that they are in competition for microRNAs (miRNA) in order to suppress expression, as there are only a limited amount of both RNAs and miRNAs. It's a passive yet controlled process by which the complexes formed can inhibit the expression of the RNAs (that can either code for a protein or not) or these complexes can de-attach from the RNAs and allow expression to occur, to which (if coding for a protein) it would be translated into a protein.

 

Talking about competition in the body in general however is a very interesting topic and nice choice of question! There is no lack of competition in or on our body, as you said before about bacterial gut competition. There are many other examples, if you want to break it down into passive and active competition you could say that Haemoglobin proteins passively compete with each other in order to obtain molecule di-oxygen. Yet also you can have virues passively competing for cells with each other in order to hijack the cells metabolism and genome expression.

 

Active examples that come to mind are as mentioned earlier bacterial colonies either in the gut, mouth or skin (depending on the resources used by those bacteria) doesn't really matter where. Another form of active competition is that of the cells, people tend to forget that your cells are constantly competing with each other, it's nice to think that organisms are just a bundle of cells that co-operatively work together in order to achieve a goal (and in some ways yes this is true) but it is also similar that those cells are competing with one another. Sugars, osmolytes, amino acids, all of these are finite resources that are essential for cell functioning, cells actively pump these molecules/compounds in through special proteins in the membrane and are therefore actively competing with one another.

 

The sperm competition is an interesting point. Yes they are competing but also assisting one another to the goal. The cell walls of the ovaries are quite deadly to sperm and those that get caught on the lining create a barrier which prevents their other companions from being killed.

 

Hope this helps to some extent

Edited January 21, 2015 by Aminoxyl

[MarkE]

Thanks for you answer, Aminoxyl, this is really helpful!

Can I conclude then that proteins are not actively in competition which each other (the way gut bacteria f.i. are), but that there is passive competition going on. You can call it ‘competition’ because some receptors in our body can take up different kind of proteins, so the body will choose this one, and not that one. If we drink coffee so we choose other proteins to bind to our receptors. Is it however true that sometimes receptors can only take up one particular protein, and also receptors sometimes are able to take up over 10 different kinds of proteins? I don't know any examples of this. Is it also true to state that proteins and receptors are all about form and polarity, and form and polarity only. If the form/polarity fits, it fits. No matter what the proteins task/funtion is (which are not always the same, like nicotin that imitates (by his form) acetylcholine). Am I saying this right?

 

 

 

Next you’re talking about competing cells.

If cells are competing with each other, how then can you see that a cells lost the battle from his colleague, and another one has won? Are some cells at some point stronger than other ones, and you already know that this one is going to survive (longer), and that one will die (earlier)? When is a cell ‘better’ than his colleague cell? You wrote “Cells actively pump these molecules/compounds in through special proteins”. Do some cells perhaps have a better pump mechanism? By the way, I read here that body cells (only?) compete with brain cells.

Next you’re talking about our blood.

“You could say that Haemoglobin proteins passively compete with each other in order to obtain molecule di-oxygen”. Very interesting, this is new to me Can you tell me more about this, in a competition-like way of course?

 

Finally the subject 'viruses'

“Yet also you can have viruses passively competing for cells with each other in order to hijack the cells metabolism and genome expression”. I didn’t know the that you can really see that they are fighting each other to get to the cell. I guess this has to be passive competition as well, because viruses are not considered 'alive', is this true?

By the way, I just read here that our DNA exists of retroviruses, did you know that? So some of them won the competition for sure!

Edited January 23, 2015 by MarkE

[MarkE]

I just found another proof of protein competition (full article here):

 

"There is competition for binding to FGFR2 and one of the two competitors, phospholipase Cγ1 (Plcγ1), will increase cancer cell metastasis. The other protein inhibits the opportunity for this to occur,"

said John Ladbury, Ph.D., professor of Biochemistry and Molecular Biology.