Skip to main content

Helixgate

Skip to main content

Helixgate

Uncategorized

Oncogenic Signaling Shaped by a Golgi Trafficking Protein Pair

Oncogenic Signaling Shaped by a Golgi Trafficking Protein Pair

Published

on

A new study in Science Signaling identifies a previously overlooked control point in receptor tyrosine kinase (RTK) signaling, one that operates not at the plasma membrane, but at the Golgi. The research, published as “Oncogenic receptor tyrosine kinase signaling is driven by the Golgi protein GOLPH3 and its interaction with MYO18A,” reveals that the Golgi‑localized proteins GOLPH3 and MYO18A act together to route RTKs to the cell surface, thereby setting the strength of growth‑factor signaling across multiple pathways.

The work was led by Kyle Starost and colleagues at Case Western Reserve University School of Medicine and the University of California, San Diego. Their findings help explain why GOLPH3 is frequently amplified in human cancers and why its overexpression correlates with poor prognosis across tumor types.

RTKs such as EGFR, insulin receptor, and PDGFR are central drivers of proliferation and survival in many cancers. Although RTK inhibitors are widely used clinically, resistance often emerges, underscoring the need for alternative strategies that modulate signaling upstream of the receptor. The new study identifies one such upstream node: the delivery of RTKs from the Golgi to the plasma membrane.

Using an unbiased signaling analysis, the team found that siRNA knockdown of GOLPH3 or MYO18A impaired phosphorylation of EGFR at Tyr1068 and Tyr1086, as well as downstream AKT and ERK signaling. These defects persisted even when PI3K/AKT/mTOR signaling was pharmacologically blocked, demonstrating that GOLPH3 acts directly at the receptor level rather than through mTOR modulation.

To pinpoint the mechanism, the researchers turned to trafficking assays. Imaging of endogenous EGFR showed that loss of GOLPH3 or MYO18A caused the receptor to accumulate in intracellular puncta rather than at the plasma membrane. A quantitative PDGFR‑GFP surface‑delivery assay confirmed that both proteins are required for Golgi‑to‑surface transport. Treatment with brefeldin A or golgicide A, which disrupt Golgi structure, produced similar reductions in surface receptor levels, reinforcing the conclusion that the GOLPH3–MYO18A complex is essential for RTK delivery.

Overexpression experiments completed the mechanistic picture. Increasing GOLPH3 or MYO18A levels enhanced EGF‑stimulated phosphorylation of EGFR and AKT, while a GOLPH3 mutant unable to bind PI4P failed to do so. These results position the GOLPH3–MYO18A complex as a central determinant of RTK availability at the cell surface.

The authors wrote, “The GOLPH3-MYO18A complex at the Golgi apparatus was required and rate-limiting for RTK signaling across the cell types and receptors assessed.” The findings suggest that targeting Golgi‑based trafficking machinery could offer a new therapeutic angle for tumors that rely on hyperactive RTK signaling or have developed resistance to RTK inhibitors.

The post Oncogenic Signaling Shaped by a Golgi Trafficking Protein Pair appeared first on GEN – Genetic Engineering and Biotechnology News.

Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Uncategorized

New webinar: Tackling drug discovery challenges in cancer research

Published

on

Cancer cells

Hosted by Drug Discovery World and supported by Sartorius and BioIVT, this webinar will explore the opportunities and challenges that exist within cancer research drug discovery and development.

You will hear from Dr Sudha Rao, Chief Scientific Officer of Kazia Therapeutics, Karol Budzik, PhD, Business Development Associate at Vyriad Therapeutics and Lars van der Veen, Chief Scientific Officer at iOnctura.

Presentations will cover how cancer treatments have shifted towards reprogramming the biology driving tumour growth, immune escape and treatment resistance, the trajectory that in vivo CAR-T treatments are taking, and how challenging tumours burdened by stroma and immune-mediated resistance can be tackled.

Q&A with the speakers follows the presentations.

Register for free now.

The post New webinar: Tackling drug discovery challenges in cancer research appeared first on Drug Discovery World (DDW).

Continue Reading

Uncategorized

Psilocybin proves promising in neuropathic pain mouse study

Published

on

Amid the rise of psychedelics in the mental health space, researchers have begun to explore psilocybin as a treatment for chemotherapy-induced peripheral neuropathy.

Continue Reading

Uncategorized

New Spectrometry Technique Could Aid Formulation Development

New Spectrometry Technique Could Aid Formulation Development

Published

on

A new technique combining two forms of spectrometry could help biopharmaceutical companies improve their choice of formulation buffer for antibody manufacturing by revealing how molecular forms and three-dimensional shapes of complex biologics respond to their environment. That’s the view of Christian Bleiholder, PhD, a professor at Florida State University who helped develop the technique.

According to Bleiholder, what happens structurally when a complex biological molecule, such as an antibody or viral spike protein, binds to its target is currently poorly understood.

“This is where [this approach] can help with the bioprocessing and formulation,” he says, as structural changes “can affect the lifespan [of the product] and lead to issues, such as aggregation.”

Because antibodies are complex, existing techniques tend to be powerful at different levels of complexity, he explains. Mass spectrometry is particularly powerful for distinguishing molecular composition, while structural approaches such as X-ray crystallography and cryo-electron microscopy can provide high-resolution structural information.

The challenge is understanding the link between these things within a heterogeneous sample, he says.

To overcome this, Bleiholder and his team worked with Bruker Daltonics to develop Tandem-Trapped Ion Mobility Spectrometry (Tandem-TIMS). This combines tandem ion mobility spectrometry with tandem mass spectrometry to disentangle three overlapping layers of molecular complexity: molecular form, three-dimensional shape, and binding or assembly state, he says.

He explains that, if the proteins have different structures, they can be characterized with tandem ion mobility spectrometry, and then mass spectrometry can be used to look at their molecular forms and binding states.

Going forward, Bleiholder hopes the technique can be used for formulation development but also earlier, during drug discovery of new products, such as multi-specific antibodies, to determine which molecular states are important and how those change when a biologic engages its target. He also plans to look at automating the technique.

Bleiholder spoke about using Tandem-TIMS at the Bioprocessing Summit in Boston earlier this year.

The post New Spectrometry Technique Could Aid Formulation Development appeared first on GEN – Genetic Engineering and Biotechnology News.

Continue Reading

Trending

Helixgate Biotech Review July Issue QR CodeScan to Read