TY - JOUR
T1 - Molecular and functional characteristics of MAP-2a
T2 - Ability of MAP-2a versus MAP-2b to induce stable microtubules in COS cells
AU - Kalcheva, Nellie
AU - Rockwood, Julia M.
AU - Kress, Yvonne
AU - Steiner, Ari
AU - Shafit-Zagardo, Bridget
PY - 1998
Y1 - 1998
N2 - Microtubule-associated protein-2 (MAP-2) is a prominent cytoskeletal protein in the mammalian nervous system. Two high-molecular-weight (HMW) MAP- 2 isoforms, MAP-2a and MAP-2b, are developmentally regulated. MAP-2b is expressed through the life of the neuron, while MAP-2a expression coincides with the time of synaptic formation. MAP-2a and MAP-2b differ in size by approximately 10 kD. Attempts to differentiate MAP-2a from MAP-2b led to the identification of additional exons; exons 7A, 8, 13, and 16. The focus of the present study was to define the complete molecular composition of MAP-2a that was prerequisite for investigating the functional characteristic of the MAP- 2a protein. Detailed examination of rat brain mRNA by Northern blot analysis and RT-PCR showed that MAP-2a contains only exon 8 in addition to the exons found in the MAP-2b transcript. Exons 7A, 13, and 16 are not present in the MAP-2a transcript. Antibody generated to exon 8 expressed protein, immunoprecipitated a HMW protein from adult rat brain that co-migrated with MAP-2a and was immunopositire with other MAP-2 antibodies. Comparative transfections of full-length MAP-2a and MAP-2b cDNA into COS-7 cells demonstrated that MAP-2a influenced the microtubule network differently than MAP-2b by inducing rapid and stable microtubule bundle formation even in the presence of nocodazole.
AB - Microtubule-associated protein-2 (MAP-2) is a prominent cytoskeletal protein in the mammalian nervous system. Two high-molecular-weight (HMW) MAP- 2 isoforms, MAP-2a and MAP-2b, are developmentally regulated. MAP-2b is expressed through the life of the neuron, while MAP-2a expression coincides with the time of synaptic formation. MAP-2a and MAP-2b differ in size by approximately 10 kD. Attempts to differentiate MAP-2a from MAP-2b led to the identification of additional exons; exons 7A, 8, 13, and 16. The focus of the present study was to define the complete molecular composition of MAP-2a that was prerequisite for investigating the functional characteristic of the MAP- 2a protein. Detailed examination of rat brain mRNA by Northern blot analysis and RT-PCR showed that MAP-2a contains only exon 8 in addition to the exons found in the MAP-2b transcript. Exons 7A, 13, and 16 are not present in the MAP-2a transcript. Antibody generated to exon 8 expressed protein, immunoprecipitated a HMW protein from adult rat brain that co-migrated with MAP-2a and was immunopositire with other MAP-2 antibodies. Comparative transfections of full-length MAP-2a and MAP-2b cDNA into COS-7 cells demonstrated that MAP-2a influenced the microtubule network differently than MAP-2b by inducing rapid and stable microtubule bundle formation even in the presence of nocodazole.
KW - Acetylated tubulin
KW - MAP-2 isoforms
KW - MAP-2a
KW - MAP-2b
KW - Microtubule bundling
KW - Microtubules
KW - Nocodazole
KW - Transient transfections
UR - http://www.scopus.com/inward/record.url?scp=0031747115&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031747115&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1097-0169(1998)40:3<272::AID-CM6>3.0.CO;2-F
DO - 10.1002/(SICI)1097-0169(1998)40:3<272::AID-CM6>3.0.CO;2-F
M3 - Article
C2 - 9678670
AN - SCOPUS:0031747115
SN - 0886-1544
VL - 40
SP - 272
EP - 285
JO - Cell Motility and the Cytoskeleton
JF - Cell Motility and the Cytoskeleton
IS - 3
ER -