Moving to a Start-up?

Not sure about other industries, but the auto-finance industry, in line with the auto industry, is changing and is more and more resembling that of a tech industry, with startups popping up left and right. Many switch over to start-ups and for various reasons (e.g., growth opportunity, culture, experience of "building something", etc.). Of course, chief among them is the huge upside potential through equity/stock option that can be literally life-changing. Are start-ups on your radar as you plan out your career path? Since start-ups wouldn't have a robust set of departments/positions as would an established, mature corporation, what are some key finance roles in demand at start-ups?