Activins / Inhibins

Available Resources for Activins / Inhibins Research

At Creative BioMart, we offer a wide range of products associated with activins/inhibins, such as recombinant proteins, protein pre-coupled magnetic beads, and cell & tissue lysates. We also provide customized services to ensure your specific needs are met.

Furthermore, we provide a plethora of resources covering various aspects of activins/inhibins, including pathways, protein function, interacting proteins, related articles, research areas, and other relevant topics. These resources are invaluable for researchers looking to enhance their understanding of activins/inhibins and their impact on physiological processes.

Our Featured Products

Cat.#	Product name	Species	Source (Host)	Tag
INHBB-2261H	Active Recombinant Human INHBB protein (Met1-Ala407), His-tagged	Human	HEK293	C-His
INHBC-02H	Recombinant Human INHBC Protein, N-His tagged	Human	HEK293	N-His
INHBE-114H	Recombinant Human INHBE, His-tagged	Human	E.coli	His
INHBE-35H	Recombinant Human INHBE Protein, N-His tagged	Human	HEK293	N-His

About Activins / Inhibins

Activins and inhibins are two closely related protein families that play important roles in regulating various physiological processes in the body. They belong to the transforming growth factor-beta (TGF-β) superfamily of proteins and are involved in cell growth, differentiation, and embryonic development.

Structure and Classification

Activins and inhibins are dimeric proteins composed of two subunits, referred to as α-subunits and β-subunits. The α-subunit is common to both activins and inhibins, while the β-subunit determines their specific functions and receptor binding properties. Activins are composed of two β-subunits, usually βA and βB, forming either homodimers (e.g., activin A, activin B) or heterodimers (e.g., activin AB). Inhibins consist of an α-subunit linked to one of two β-subunits, βA or βB, forming inhibin A (αβA) or inhibin B (αβB), respectively.

Activins

Activins are primarily known for their role as growth factors and regulators of cell differentiation. They function by binding to specific cell surface receptors called activin receptors. Activin signaling activates downstream signaling pathways, including the Smad pathway, leading to changes in gene expression and cellular responses. Activins are involved in various processes, including embryonic development, reproductive function, tissue repair, and immune regulation. They play a role in regulating cell proliferation, differentiation, and apoptosis in different tissues and organs.

Inhibins

Inhibins, as the name suggests, act as inhibitors of activin signaling. They competitively bind to activin receptors and prevent activins from binding and activating downstream signaling pathways. Inhibins primarily regulate the secretion of follicle-stimulating hormone (FSH) from the pituitary gland. Inhibin A, produced by ovarian granulosa cells, suppresses FSH secretion, helping to maintain a balanced reproductive cycle. Inhibin B, produced by the testes in males and granulosa cells in females, also plays a role in regulating FSH levels and follicular development. Inhibins are essential for feedback control of the reproductive system and contribute to the regulation of fertility.

Understanding the concepts and roles of activins and inhibins provides insights into their physiological significance and their potential as therapeutic targets in various diseases. The balance between activin and inhibin signaling is crucial for maintaining proper cellular processes and overall homeostasis in the body.

Fig.1 Activin and inhibin processing and signaling. (Namwanje M, et al., 2016)

Signaling Pathways of Activins and Inhibins in Activity Regulation

The signaling pathways of activins and inhibins involve the binding of these proteins to specific cell surface receptors and the subsequent activation of intracellular signaling cascades.

Activins bind to type II receptors, primarily activin receptor type IIA (ActRIIA) and activin receptor type IIB (ActRIIB). This binding leads to the recruitment and phosphorylation of type I receptors, such as activin receptor-like kinase 4 (ALK4) and activin receptor-like kinase 7 (ALK7). The activated type I receptors phosphorylate downstream proteins called Smads, specifically Smad2 and Smad3. These phosphorylated Smads form complexes with Smad4 and translocate into the nucleus, where they regulate the expression of target genes involved in cell growth, differentiation, and other cellular processes.

Inhibins, by competing with activins for binding to the same receptors, inhibit activin signaling. Through their interaction with type II receptors, inhibins prevent the activation of downstream signaling pathways, including the Smad pathway. This leads to the suppression of target gene expression and the modulation of cellular responses.

In addition to the Smad-dependent pathway, activins and inhibins can also activate non-Smad signaling pathways, such as the mitogen-activated protein kinase (MAPK) pathway and the phosphoinositide 3-kinase (PI3K)/Akt pathway. These additional pathways further modulate cellular responses to activin and inhibin signaling, providing additional layers of regulation.

Overall, the signaling pathways of activins and inhibins are complex and involve the activation of multiple intracellular signaling cascades, which collectively regulate various cellular processes and contribute to the proper functioning of the reproductive system and other tissues.

The Role of Activins / Inhibins

Role of Activins and Inhibins in Cell Growth, Differentiation, and Development

Activins and inhibins play essential roles in cell growth, differentiation, and development processes.

• Activins promote cell proliferation and differentiation in various tissues. They regulate the growth and development of different cell types, including neurons, muscle cells, and immune cells. Activins also contribute to tissue repair and regeneration by stimulating cell division and promoting the formation of new cells. In embryonic development, activins participate in cell fate determination, tissue patterning, and organogenesis.
• In contrast, inhibins act as negative regulators of cell growth and differentiation. By inhibiting activin signaling, inhibins help maintain a balance in cell proliferation and differentiation processes. Inhibins prevent excessive cell growth and ensure proper tissue development by suppressing the stimulatory effects of activins.

Roles and Regulation of Activins and Inhibins in the Reproductive System

Activins and inhibins play crucial roles in the regulation of the reproductive system in both males and females.

• In females, activins are involved in follicle development, ovulation, and corpus luteum formation. They promote the growth and maturation of ovarian follicles, which contain the eggs. Activins also modulate hormone secretion in the ovaries, including the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland. Inhibin A, produced by ovarian granulosa cells, acts as a negative feedback regulator of FSH secretion. It helps maintain a balanced reproductive cycle by suppressing FSH levels when necessary. In males, activins regulate spermatogenesis and testosterone production.
• Inhibins, on the other hand, provide feedback control in the reproductive system. In females, inhibin A and inhibin B, produced by ovarian granulosa cells, suppress FSH secretion, preventing excessive follicular development and maintaining hormonal balance. In males, inhibin B, produced by the testes, regulates FSH levels and influences sperm production.

The production of activins and inhibins in the reproductive system is tightly regulated. Their synthesis and secretion are influenced by various factors, including gonadotropin-releasing hormone (GnRH), FSH, LH, and other local regulatory molecules. This complex regulation ensures proper reproductive function and the maintenance of fertility.

Fig.2 Activins and inhibins in ovarian folliculogenesis and pregnancy. (Namwanje M, et al., 2016)

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References:

1. 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
2. Hagg A, O'Shea E, Harrison CA, Walton KL. Targeting activins and inhibins to treat reproductive disorders and cancer cachexia. J Endocrinol. 2023;258(1):e220290. Published 2023 Jun 26. doi:10.1530/JOE-22-0290