Decrease of tyrosine-O-sulfate-containing proteins found in rat fibroblasts infected with Rous sarcoma virus or...

Area of Science:

• Biochemistry
• Cell Biology
• Oncology

Background:

• Tyrosine sulfation is a post-translational modification found in various proteins.
• Malignant transformation can alter protein modifications, impacting cellular function.
• Previous work suggested general sulfation changes in transformed tissues.

Purpose of the Study:

• To investigate the effect of sarcoma virus infection on tyrosine sulfation in rat fibroblasts.
• To compare sulfation levels in normal versus virally transformed cells.
• To examine the role of temperature-sensitive viral mutants in altering sulfation.

Main Methods:

• Incubation of rat fibroblasts (3Y1) with [35S]sulfate.
• Analysis of protein sulfation following Pronase hydrolysis.
• Comparison of sulfation in cells infected with Rous sarcoma virus and Fujinami sarcoma virus (including a temperature-sensitive mutant).
• Measurement of inorganic [35S]sulfate uptake by cells.

Main Results:

• Sarcoma virus infection led to a general reduction in protein tyrosine sulfation in fibroblasts.
• Permanently transformed fibroblasts showed the greatest reduction in sulfation.
• Temperature-sensitive Fujinami sarcoma virus-transformed cells exhibited reduced sulfation at the permissive temperature.
• Sulfate uptake was reduced in permanently infected cells but not significantly different in temperature-sensitive cells at varying temperatures.
• Fibronectin released from temperature-sensitive cells at the permissive temperature contained tyrosine O-sulfate.

Conclusions:

• Viral transformation significantly impacts protein tyrosine sulfation in fibroblasts.
• Tyrosine O-sulfation of fibronectin is observed in transformed cells.
• The findings suggest a link between malignant transformation and altered tyrosine sulfation patterns.