In layman’s terms, transforming growth factors(TGF) refers to two groups of polypeptides, namely TGF-α and TGF-β. At a basic level, polypeptides are a group of amino acids- the building blocks of protein. TGF(also called tumor growth factors) performs various biological functions that promote cellular growth and differentiation. Cell differentiation occurs when your cells change as they develop to perform specialized roles over time. I hope you’re now up to speed regarding TGF.
Human tumor growth factor alpha (TGF-α) and TGF-β have different structures and operate through different mechanisms to achieve various results. However, the two TGFs don’t always lead to cell transformation, nor are they the only factors responsible for the cellular change.
Full disclosure is the kind of discussion that can easily make anyone zone out. But I’ll try not to bombard you with too much technical jargon. It’s a tough task, but here we are. Here’s a savvy and detailed look at the critical differences between TGF alpha(α) and beta (β).
TGF-α is a growth factor relating to cells on the outermost part of the skin and covering other body organs. It induces tissue development surrounding hollow structures in the body and the alimentary canal- food passageway.
TGF-α is produced in the brain, on the skin, and by cells responsible for detecting and destroying harmful microorganisms in the body. Generally, TGF-α promotes the increase of cells in the body through growth or cell division.
On the other hand, TGF-β is based on a category of proteins called cytokines. These proteins are part of the body’s inflammatory process and serve as signaling passages.
Cell signaling is simply the process through which your cells receive or transmit the signals they receive from the body or surrounding environment. TGF-β may encourage or inhibit cell growth depending on the prevailing factors or cell type.
Although TGF-α and TGF-β are polypeptide factors that act through signaling to adjust cell functions, they are different. Their differences hinge on two factors, namely:
- Genetic makeup – each growth factor has a different genetic code
- Structure- the composition of each growth factor
Up-close Look at The Differences
- Production Site
The gastric mucosa is responsible for the production of TGF-α. Your stomach’s inner surface is lined with mucous glands as part of your digestive tract. These glands are what are referred to as gastric mucosa.
Comparative studies suggest that TGF-α plays a pivotal physiological role by promoting the normal functioning of cells lining your skin, blood vessels, and organs (generally termed as epithelial cells). Conversely, all types of white blood cells in your body can produce TGF-β. Thus TGF-β is not localized in specific production sites.
There’s only one type of TGF-α, and its expression in bodily tissues has been implicated, through research, in cell migration and growth. Besides targeting skin cells, TGF-α is associated with nerve cells, the gastrointestinal tract, liver, gonads, and kidneys.
On the other hand, TGF-β exists in three subtypes (TGF-β3, TGF-β2, and TGF-β1). They are known to raise the number of receptors on cells among people with Marfan syndrome or other forms of human cancers. Consequently, such individuals are more sensitive to medication or hormonal changes. Researchers argue that TGF-βs can foster the progression of cancer cells by promoting cellular interactions in the host.
Experts also believe that TGF-β1 is responsible for the origination or development of pre-eclampsia (high blood pressure during pregnancy). Fortunately, TGF-β also plays an important role that includes:
- Tissue regeneration- rebuilding
- Cell differentiation- change in form to perform unique roles
- Embryonic development- critical during pregnancy
- Immune regulation- stimulating response to infection, promoting healing, and resolving inflammation
- Genetic Coding
TGFA genes encode TGF-α proteins. On the flip side, TGF-β1, TGF-β2, and TGF-β3 are encoded by TGFB1, TGFB2, and TGFB3, respectively. The diverse gene codes result in various forms of gene expression at the cellular level. You must be wondering what this means.
Well, gene expression involves the process through which your cells interpret information (genetic code in their DNA). As a result, growth factors affect cellular characteristics and functions.
TGF-α is made up of 160 amino acids, while TGF beta comprises 380-412 amino acids. In that light, their amino acid length is different, and so is their sequence- arrangement. Thus TGF-β has a more extended and more complex sequence than its counterpart. Generally, TGF-β1 consists of 390 amino acids, while TGF-β2 and TGF-β3 contain 412 amino acids each.
The fundamental differences between TGF-α and TGF-β lie in their structure and genetic coding. Although they perform nearly similar roles, a clear distinction exists in their definition, content, type, and production site.