Activin Family
Available Resources for the Study of Activin Family
At Creative BioMart, we are dedicated to advancing research on the activin family. Our ongoing commitment is to ensure that researchers have access to the latest tools and information about the activin family (including activin modulators, activin receptors, and activins/inhibins).
- With an extensive product portfolio, we offer a diverse range of recombinant proteins, protein pre-coupled magnetic beads, cell and tissue lysates, and more. These high-quality products are instrumental in unraveling the functions and mechanisms of various components within the activin family.
- Our team comprises experienced experts with profound expertise in activin family research. We are devoted to tailoring solutions to address the specific requirements of each researcher, empowering them with the tools they need to achieve their objectives.
- Moreover, we provide comprehensive resource support, encompassing pathways, protein function, interacting proteins, and other valuable information. By curating and providing these resources, we aim to maximize the impact of research endeavors.
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About Activin Family
The activin family is a group of proteins that belong to the transforming growth factor-beta (TGF-β) superfamily. It includes activin receptors, activins, and their modulators, such as inhibins and follistatin. This family of proteins plays critical roles in various physiological processes, including cell growth, differentiation, embryonic development, and reproductive function.
Activin Receptors
Activin receptors are transmembrane proteins that serve as cell surface receptors for activins and other ligands within the TGF-β superfamily. The two primary types of activin receptors are activin receptor type I (ActRI) and activin receptor type II (ActRII). There are multiple isoforms of each receptor, including ActRIIA, ActRIIB, and ActRIIC. These receptors are involved in mediating the cellular responses triggered by activin binding.
Activins
Activins are dimeric proteins composed of two β-subunits. They can exist in different forms, including homodimers (e.g., activin A, activin B) and heterodimers (e.g., activin AB). Activins bind to the extracellular domain of type II receptors, primarily ActRIIA and ActRIIB. This binding leads to the recruitment and phosphorylation of type I receptors, such as ALK4 and ALK7. Activin signaling pathways, including the Smad pathway, are activated upon receptor activation, resulting in changes in gene expression and cellular responses.
Activins play diverse roles in various tissues and organs. They are involved in processes such as embryonic development, cell proliferation, differentiation, tissue repair, immune regulation, and reproductive function. Activins regulate the growth and differentiation of different cell types, including neurons, muscle cells, and immune cells.
Inhibins
Inhibins, closely related to activins, are also dimeric proteins composed of an α-subunit and one of two β-subunits, βA or βB. The inhibin α-subunit is common to both inhibin A (αβA) and inhibin B (αβB). Inhibins primarily act as negative regulators of activin signaling. They competitively bind to activin receptors, preventing activins from binding and activating downstream signaling pathways. Inhibins, particularly inhibin A and inhibin B, play crucial roles in the regulation of the reproductive system by modulating the secretion of follicle-stimulating hormone (FSH) from the pituitary gland. They help maintain a balanced reproductive cycle and contribute to the regulation of fertility.
Activin Modulators
Follistatin is an important activin modulator that binds to activins and inhibits their activity. It serves as a neutralizing protein by sequestering activin ligands and preventing their interaction with receptors. Follistatin can regulate activin signaling and modulate cellular responses. Other proteins, such as the follistatin-related gene (FLRG) and cripto-1, also interact with activins and modulate their activity, although their specific roles are still being investigated.
In summary, the activin family comprises activin receptors, activins, inhibins, and modulators such as follistatin. Activins bind to their receptors, activating signaling pathways involved in cell growth, differentiation, and development. Inhibins act as negative regulators of activin signaling and play specific roles in the reproductive system. The interactions between activins, inhibins, and their modulators contribute to the fine-tuning of cellular responses and the maintenance of physiological processes in various tissues and organs.
Fig.1 Regulation of activin signaling. (Namwanje M, et al., 2016)
Importance of the Activin Family in Disease
The dysregulation of activin signaling can have significant implications for various diseases, including cancer, inflammatory disorders, and reproductive disorders. Here is an overview of how the activin family is involved in these conditions:
Cancer
- Activin signaling is involved in both promoting and inhibiting cancer development and progression, depending on the context and type of cancer. In some cancers, such as colorectal, breast, and ovarian cancers, activin signaling pathways can act as tumor suppressors by inhibiting cell proliferation, inducing apoptosis (programmed cell death), and suppressing tumor angiogenesis (the formation of new blood vessels to support tumor growth). Loss of activin signaling or mutations in activin receptors can lead to uncontrolled cell growth and tumor progression.
- On the other hand, activin signaling can also contribute to cancer progression in certain contexts. Activins can promote tumor cell migration, invasion, and metastasis. Additionally, activins may stimulate the growth of cancer-associated fibroblasts, which can create a tumor-supportive microenvironment. Overexpression of activins or dysregulation of activin receptors has been observed in various cancers, including pancreatic, lung, and prostate cancers.
Inflammatory Disorders
- The activin family is involved in regulating immune responses and inflammation. Activins can modulate the production of pro-inflammatory cytokines and chemokines, affecting the balance between pro-inflammatory and anti-inflammatory signals. Dysregulation of activin signaling has been implicated in chronic inflammatory disorders, such as rheumatoid arthritis, inflammatory bowel disease, and asthma. In these conditions, abnormal activin signaling can contribute to excessive inflammation and tissue damage.
Reproductive Disorders
- The activin family plays crucial roles in reproductive function, and dysregulation of activin signaling can lead to various reproductive disorders. In females, abnormalities in activin signaling can contribute to disorders such as polycystic ovary syndrome (PCOS), endometriosis, and ovarian cancer. In males, disruptions in activin signaling can impact spermatogenesis and fertility.
- PCOS, a common hormonal disorder in women, is associated with elevated levels of activins and altered activin/inhibin ratios. These imbalances can affect follicular development and disrupt normal ovarian function. In endometriosis, excessive activin production has been observed, contributing to the growth and survival of endometrial tissue outside the uterus. Inhibin deficiencies or mutations in inhibin genes can also lead to reproductive disorders, including infertility and premature ovarian failure.
Fig.2 The activin/TGFβ signaling network in pancreatic cancer. (Qiu W, et al., 2021)
Overall, the dysregulation of activin signaling can impact various diseases, including cancer, inflammatory disorders, and reproductive disorders. Understanding the roles of the activin family in these conditions can provide insights into potential therapeutic targets and strategies for managing these diseases.
We are committed to helping you achieve your scientific goals and make meaningful contributions to research on the roles of the various components of the activin family and their role in disease. Contact us today to learn more about our products and resources.
References:
- Namwanje M, Brown CW. Activins and Inhibins: Roles in Development, Physiology, and Disease. Cold Spring Harb Perspect Biol. 2016;8(7):a021881. Published 2016 Jul 1. doi:10.1101/cshperspect.a021881
- Hing T T, Basir R, Kuang C Y, et al. Activin A: Its Role and Involvement in Inflammatory Diseases[J]. Goal of Pertanika, 2015: 163.
- Qiu W, Kuo C-Y, Tian Y, Su GH. Dual Roles of the Activin Signaling Pathway in Pancreatic Cancer. Biomedicines. 2021; 9(7):821.
