Legal Question in Employment Law in California

Unless you have been criminally charged or there is a potential for that to happen, you won't be able to take the fifth. Maybe you can call the subpoenaing lawyer and find out what they want from you so that you have an idea. You can also bring a lawyer with you if that would make you feel more comfortable. If you are still working for the company and you are subpoenaed in connection with your work there, you could ask the company to pay your regular wages while you are at the deposition since it would be work-related.