I guess the file in attachment might be helpful for you.

I guess the file in attachment might be helpful for you.

Usually cells differentiate without serum, leading to a more elongated structure. Serum has different growth factors which contribute to increased cell proliferation, therefore cells will grow more slowly without serum .

Thanks to both the replies. But I am not very clear still in understanding the elongated morphology in absence of serum, though slower growth rate can be correlated with the same. However those same cells when again grown in serum complemented media, regains its original morphology. With very less or no growth supplements, why do cells become elongated and how elongated structure selectively provide advantage if any in serum free media?

Dear Aditya,

In general, the shape of a cell depend on "active" and "passive" factors:

- in case of a disequilibrium of ion composition (intra/extra), the cell can swallow because of entry of water (passive),

-the cytosqueleton under the plasmic membrane is responsible of active traction, leading to particular shapes (ie red blood cells have the shape of a torus, with precise reasons).

During abnormalities (ie hereditary spherocytosis for RBC) the "active" shape is lost and the cell acquires the spontaneous shape it can: a sphere (genetic default of ankirine, fixing the cytosqueleton to the  internal face of the membrane).

The second point is that cytosquelton is actively linked to some proteins like  FAK kinases: important in transmission of informations from external adhesive protein to some genes implicated in cell functionning, like cell division  and proliferation, but also differentiation .

For monocyte  in culture, when the cell adheres to the plastic , it triggers the differentiation of the cell in macrophage by intracellular activation due to fixation of adhesin,  and activation of FAK kinase ... and so on.

Last point, some cells have two different phenotypes (ie endothelial cells) , variable according to external conditions: proliferative (dynamic) or secretory( metabolism and reserve) and also  there is a link with  adhesines (ie integrin on membrane + laminin of the basal membrane of vessels) and these phenotypes.

So, if we return to your example, and we have to know which sort of cells you are speaking  about, I could imagine the  possibilities:

- without "proliferant nutrient" (FCS or other) cells could have  a adhesive phenotype, don't divide or proliferate, and have a shape elongated, eventually corresponding to some movment (you could film them perhaps),

- with serum, they can have a secretory phenotype, can divide and differentiate, and proliferate: so round shape, that we find during cell division ...

Hypothesis which could be verified measuring level of tnra cellular makers (protein expression, cyclines for division ...);

My opinion

Best regards

Didier