Kinesin family in murine central nervous system.

Abstract

Abstract. In neuronal axons, various kinds of membranous components are transported along microtubules bidirectionally. However, only two kinds of mechanochemical motor proteins, kinesin and brain dynein, had been identified as transporters of membranous organelles in mammalian neurons. Recently, a series of genes that encode proteins closely related to kinesin heavy chain were identified in several organisms including Schizosaccharomyces pombe, Aspergillus niddulans, Saccharomyces cerevisiae, Caenorhabditus elegans, and Drosophila. Most of these members of the kinesin family ale implicated in mechanisms of mitosis or meiosis. To address the mechanism of intracellular organelle transport at a molecular level, we have cloned and characterized five different members , that encode the microtubule-associated motor domain homologous to kinesin heavy chain, in murine brain tissue. Homology analysis of amino acid sequence indicated that KIF1 and KIF5 are mufine counterparts of uric/04 and kinesin heavy chain, respectively, while KIF2, KIF3, and KIF4 are as yet unidentified new species. Complete amino acid sequence of KIF3 revealed that KIF3 consists of NH2-terminal motor domain, central a-helical rod domain, and COOH-terminal globular domain. Complete amino acid sequence of KIF2 revealed that KIF2 consists of NH~-terminal globular domain, central motor domain, and COOH-terminal or-helical rod domain. This is the first identification of the kinesin-related protein which has its motor domain at the central part in its primary structure. Northern blot analysis revealed that KIFI, KIF3, and KIF5 are expressed almost exclusively in murine brain, whereas KIF2 and KIF4 are expressed in brain as well as in other tissues. All these members of the kinesin family are expressed in the same type of neurons, and thus each one of them may transport its specific organelle in the murine central nervous system.

Two Kinesin Light Chain Genes in Mice

“…Multiple KLC Genes in Mice-Although several different kinesin heavy chain genes were identified in M. musculus (43)(44)(45), only one gene for kinesin light chain has been cloned from various nonmammalian sources (25)(26)(27). In humans, Niclas et al (1) reported two kinesin heavy chain genes; one is expressed in a neuronal distribution, while the other was present in a ubiquitous manner.…”

“…Thus, an efficient cellular transport mechanism is required, possibly involving several families of molecular motors, each performing a unique function. At least 10 different kinesin-like molecules have already been identified (37,43,45,(47)(48)(49)(50)(51) in mouse brain, and more remain to be discovered. Given the complex organization of the mammalian neuron, it is possible that the two kinesin light chains in mouse perform different functions within the cell, although they may be functionally redundant.…”

Kif2C Minimal Functional Domain Has Unusual Nucleotide Binding Properties That Are Adapted to Microtubule Depolymerization

“…Kinesin-13 family, also known as internal kinesins, is a unique family of kinesins in which the motor domain is internal to the polypeptide chain (10,11). Stemming from conventional kinesins (12), kinesin-13 proteins have evolved a distinct function of MT depolymerization rather than walking along MT protofilaments (11,13).…”

Kinectin-Kinesin Binding Domains and Their Effects on Organelle Motility

“…Actin-dependent organelle motility has also been proposed to be important for various short range cellular processes (3,4). In these active transport systems, motor proteins are regulated to move membrane organelles to specific target compartments (5)(6)(7)(8)(9)(10). Among the motor proteins, kinesin or its family members power the plus-end-directed MT-based motility (11,12), while cytoplasmic dynein or its family members drive the minus-end directed motility (13)(14)(15).…”