Growth factors mediate their diverse biologic responses (regulation of cellular proliferation. differentiation. migration and survival) by binding to and activating cell-surface receptors with intrinsic protein kinase activity named Receptor Tyrosine Kinases (RTKs). About 60 RTKs have been identified and can be classified into more than 16 different receptor families. https://danddcollectiblers.shop/product-category/tool-bag/