Microtubule-associated proteins 1A and LC2. Two proteins encoded in one messenger RNA

• Published in: The Journal of biological chemistry Vol. 267; no. 23; pp. 16561 - 16566
• Main Authors: LANGKOPF, A, HAMMARBACK, J. A, MÜLLER, R, VALLEE, R. B, GARNER, C. C
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 15.08.1992
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Blotting, Northern; Brain - physiology; Cattle; cDNA; Cloning, Molecular; DNA Probes; Fundamental and applied biological sciences. Psychology; Gene Library; genes; Genes. Genome; Macromolecular Substances; microtubule-associated protein 1A; microtubule-associated protein LC2; Microtubule-Associated Proteins - genetics; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; nucleotide sequence; Oligodeoxyribonucleotides; Polymerase Chain Reaction - methods; predictions; Rats; Restriction Mapping; RNA - genetics; RNA - isolation & purification; RNA, Messenger - genetics; RNA, Messenger - metabolism; Sequence Homology, Nucleic Acid; Northern blotting; Vertebrata; Mammalia; Complementary DNA; Rat; Rodentia; Primary structure; Microtubule associated protein; Gene expression; Brain (vertebrata); Immunological method
• DOI: 10.1016/s0021-9258(18)42039-x
• ISSN: 0021-9258

The deduced amino acid sequence for the filamentous microtubule-associated protein (MAP) 1A, thought to be involved in stabilizing the mature neuronal cytoskeleton, has been determined from a series of overlapping cDNA clones. Though previously described as biochemically and immunologically distinct from MAP1B, we now demonstrate that MAP1A is structurally related to MAP1B, a protein associated with neurite outgrowth and process plasticity. The two MAPs exhibit regional amino acid sequence similarities spanning their potential microtubule binding domains placing both into a new MAP family. The cDNA sequence encoding MAP1A was also found to encode one of its associated light chains (LC) called LC2. Both proteins are found on a single mRNA in the same open reading frame and are translated as a pre-MAP1A/LC2-protein. The topological relationship between MAP1A and LC2 coding sequences is, therefore, identical to that previously shown for MAP1B and LC1 (Hammarback, J. A., Obar, R. A., Hughes, S. M., and Vallee, R. B. (1991) Neuron 7, 129-139). Based on these and earlier results, we conclude that LC1 and LC2 are structurally related polypeptides generated from distinct MAP polyprotein precursors but free to exchange between the two MAPs.