Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organ... more Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organelle transport in neurons. Our recent studies showed that KIF3AC is as processive as conventional kinesin-1 suggesting that their ATPase mechanochemistry may be similar. However, the presence of two different motor polypeptides in KIF3AC implies that there must be a cellular advantage for the KIF3AC heterodimer. The hypothesis tested was whether there is an intrinsic bias within KIF3AC such that either KIF3A or KIF3C initiates the processive run. To pursue these experiments a mechanistic approach was used to compare the presteady-state kinetics of KIF3AC to the kinetics of homodimeric KIF3AA and KIF3CC. The results indicate that microtubule collision at 11.4 μᴍ(-1)s(-1) coupled with ADP release at 78 s(-1) are fast steps for homodimeric KIF3AA. In contrast, KIF3CC exhibits much slower microtubule association at 2.1 μᴍ(-1)s(-1) and ADP release at 8 s(-1). For KIF3AC, microtubule associati...
Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organ... more Mammalian KIF3AC contains two distinct motor polypeptides and is best known for its role in organelle transport in neurons. Our recent studies showed that KIF3AC is as processive as conventional kinesin-1 suggesting that their ATPase mechanochemistry may be similar. However, the presence of two different motor polypeptides in KIF3AC implies that there must be a cellular advantage for the KIF3AC heterodimer. The hypothesis tested was whether there is an intrinsic bias within KIF3AC such that either KIF3A or KIF3C initiates the processive run. To pursue these experiments a mechanistic approach was used to compare the presteady-state kinetics of KIF3AC to the kinetics of homodimeric KIF3AA and KIF3CC. The results indicate that microtubule collision at 11.4 μᴍ(-1)s(-1) coupled with ADP release at 78 s(-1) are fast steps for homodimeric KIF3AA. In contrast, KIF3CC exhibits much slower microtubule association at 2.1 μᴍ(-1)s(-1) and ADP release at 8 s(-1). For KIF3AC, microtubule associati...
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Papers by ivan rayment