Considering the pathophysiology of osteoporosis, what are the effects of extracellular signal regulated kinases (ERKs) and receptor activator of RANKL on osteoblasts and osteoclasts?

Considering the pathophysiology of osteoporosis, what are the effects of extracellular signal regulated kinases (ERKs) and receptor activator of RANKL on osteoblasts and osteoclasts?