Microtubule stability: dynamic; gtp required for assembly, but hydrolysis is not required. When does microtubule collapse? when gtp cap is lost. Actin filament binds to atp rather than gtp. True. actin is normally bound to atp, but it also can be bound to _____. _______ inhibits microfilaments formation, and ______ stimulates microfilament formation. Integral membrane proteins are linked _______ to the cytoskeleton. indirectly. Arp protein initiate formation from ______ end, formins add actin to the ________ end. minus, plus. Gap junctions adheren junctions are mediated by cadherin cytosolic component of cadherin interacts indirectly with ________. cytoskeletal elements. Extra cellular component requires calcium as well to interact with another cadherin. True. what are 2 of the transmembrane protein in tight junctions? occluding and claudin; mediate interaction with the cytoskeleton. 1200 da; polymers like dna and rna and polysaccharides cannot move through. Where do we find connexions? in the channels of gap junctions. Protein polysaccharide complexes, associated with large modified sugars.