Which of the following statements is false?
(a) mutations in the kit receptor are seen in familial cancer syndromes
(b) cytoskeleton-associated proteins are ligands for integrins
(c) src is a tyrosine kinase
(d) in the jak-stat pathway, ligand binding promotes phosphorylation, dimerization and nuclear translocation of transcription activators
(e) in normal cells, rtk dimerization and autophosphorylation (transphosphorylation) are dependent on ligand binding.

(E) in normal cells, RTK dimerization and autophosphorylation (transphosphorylation) are dependent on ligand binding.

Explanation:

It has only been recently discovered that there are RTK's that exist as inactive oligomers/dimers even prior ligand binding and that autophosphorylation sites are phosphorylated in a specific order.    

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.