Illustration of PkcA and SepA proteins interacting within a fungal cell.

Decoding Cell Growth: How a Fungal Protein Duo Could Revolutionize Medicine

Author's portrait.
Lena Kashyap in Science & Nature August 2025 • 5 min read.

"New research unveils the intricate relationship between two key proteins in fungal cell development, offering potential breakthroughs in treating diseases from fungal infections to cancer."


Cell growth and division are fundamental processes of life, essential for development, repair, and reproduction. However, when these processes go awry, the consequences can be dire, leading to diseases like cancer and persistent infections. Understanding the intricate mechanisms that govern cell behavior is therefore paramount. Recent research has shed light on a critical interaction between two key proteins within fungal cells, offering new insights into how cell growth is regulated.

The study, focused on the fungus Aspergillus nidulans, investigates the interplay between protein kinase C (PkcA) and formin SepA, two proteins known to play vital roles in polarized cell growth. Polarized growth is a type of cell growth where new materials are added to specific locations on the cell surface, allowing the cell to develop in a directed manner. This is particularly important in fungi, which grow as long, branching filaments.

This research dives deep into the world of cellular mechanisms, and it has the potential to influence the development of new medical treatments. By understanding how PkcA and SepA interact, scientists may be able to identify weak points in fungal growth and division, opening the door for more effective antifungal drugs and potential cancer therapies.

The Dynamic Duo: PkcA and SepA

Illustration of PkcA and SepA proteins interacting within a fungal cell.

PkcA and SepA are not new to the world of cell biology. PkcA, an enzyme, acts like a master regulator, influencing various cellular processes. SepA, on the other hand, is a formin protein, crucial for building the cell's internal skeleton, primarily composed of actin filaments. These filaments are essential for maintaining cell shape, movement, and division. Think of PkcA as the architect and SepA as the construction worker; both are needed to build and maintain a healthy, functional cell.

Previous studies have hinted at a connection between PkcA and SepA, but this new research provides concrete evidence of their direct interaction. The scientists used sophisticated techniques, including bimolecular fluorescence complementation (BiFC) and yeast two-hybrid assays, to demonstrate that PkcA and SepA physically bind to each other within the cell. This interaction is particularly evident at hyphal tips (the growing points of fungal filaments) and at septation sites (where new cell walls are formed).

Key findings from the study include: PkcA and SepA form a complex at hyphal tips and septation sites. This complex is essential for polarized cell growth. Actin, another key component of the cell's cytoskeleton, plays a role in the formation and stability of the PkcA/SepA complex. Disrupting the interaction between PkcA and SepA can disrupt normal cell growth and division.
The researchers also discovered that a specific region of SepA, called the FH2 domain, is critical for its interaction with PkcA. By manipulating this domain, they could disrupt the formation of the PkcA/SepA complex, leading to abnormal cell growth. Imagine trying to build a house with a faulty blueprint; the resulting structure will likely be unstable and prone to collapse. Similarly, disrupting the interaction between PkcA and SepA throws off the delicate balance of cell growth, leading to defects in cell shape and division.

Implications and Future Directions

This research has significant implications for our understanding of cell growth and division. By identifying the PkcA/SepA complex as a key regulator of these processes, scientists have opened up new avenues for developing targeted therapies. For example, drugs that disrupt the interaction between PkcA and SepA could be used to treat fungal infections by preventing the fungus from growing and spreading. The selective disruption of this interaction is an ideal method, as it minimizes side effects to the patient.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.fgb.2018.10.002, Alternate LINK

Title: Aspergillus Nidulans Protein Kinase C Forms A Complex With The Formin Sepa That Is Involved In Apical Growth And Septation

Subject: Genetics

Journal: Fungal Genetics and Biology

Publisher: Elsevier BV

Authors: Loretta Jackson-Hayes, Zainab Atiq, Brianna Betton, W. Toler Freyaldenhoven, Lance Myers, Elisabet Olsen, Terry W. Hill

Published: 2019-01-01

Everything You Need To Know

1

What roles do PkcA and SepA play in cell growth, and what happens when they don't work together properly?

PkcA, or protein kinase C, acts as a master regulator influencing various cellular processes. SepA, a formin protein, is crucial for building the cell's internal skeleton, primarily composed of actin filaments. PkcA can be seen as the architect and SepA as the construction worker, both needed to maintain a healthy, functional cell. Disrupting the interactions between these two has the potential to disrupt normal cell growth and division.

2

Which specific fungus was studied to reveal the interaction between PkcA and SepA, and what is polarized cell growth?

This study focused on the fungus *Aspergillus nidulans*, examining the interplay between protein kinase C (PkcA) and formin SepA, two proteins known to play vital roles in polarized cell growth. Polarized growth is a type of cell growth where new materials are added to specific locations on the cell surface, allowing the cell to develop in a directed manner, which is important in fungi growing as long, branching filaments.

3

What key findings emerged regarding the PkcA/SepA complex, and how does the cytoskeleton factor into this?

The research highlights the formation of a complex between PkcA and SepA at hyphal tips and septation sites as essential for polarized cell growth. Actin, a key component of the cell's cytoskeleton, plays a role in the formation and stability of this PkcA/SepA complex. Disruption of the interaction between PkcA and SepA can lead to abnormal cell growth and division.

4

What is the significance of the FH2 domain in the interaction between SepA and PkcA, and what analogy helps explain the consequences of disrupting this interaction?

The FH2 domain is a specific region of SepA that is critical for its interaction with PkcA. Manipulating this domain can disrupt the formation of the PkcA/SepA complex, leading to abnormal cell growth. This is likened to building a house with a faulty blueprint, where the resulting structure is unstable.

5

How might understanding the interaction between PkcA and SepA lead to new medical treatments, and what diseases could potentially be targeted?

Targeting the interaction between PkcA and SepA could lead to new therapies. Drugs that disrupt the interaction between PkcA and SepA could be used to treat fungal infections by preventing the fungus from growing and spreading. The selective disruption of this interaction is an ideal method, as it minimizes side effects to the patient. Additionaly, because cell growth is also a factor in cancer development, this also opens doors to the development of cancer therapies.

Newsletter Subscribe

Subscribe to get the latest articles and insights directly in your inbox.