question: What is the proteoglycan Tsukushi?
answer: Tsukushi (TSK), a member of the small leucine-rich repeat proteoglycan (SLRP) family, plays multifunctional roles by interacting with signaling molecules during development.
  In lung cancer cells, TSK is expressed more highly than the other SLRPs family members, and regulates the EMT and proliferation. Thus, TSK may be a key coordinator of multiple pathways and an important structural element in the lung cancer microenvironment.
  Gain- and loss-of-function analyses showed that the small leucine-rich proteoglycan, tsukushi, contributes to vitamin K2-mediated enhancement of collagen accumulation.