22873
The severe defects in growth plate development caused by chondrocyte extracellular signal - regulated protein kinases 1 and 2 ( ERK1 / 2 ) gain or loss - of - function suggest that tight spatial and temporal regulation of mitogen - activated protein kinase signaling is necessary to achieve harmonious growth plate elongation and structure .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None