Alternative splicing in protein associated with Myc (Pam) influences its binding to c-Myc
Article first published online: 8 DEC 2005
Copyright © 2005 Wiley-Liss, Inc.
Journal of Neuroscience Research
Volume 83, Issue 2, pages 222–232, 1 February 2006
How to Cite
Santos, T. M., Han, S., Bowser, M., Sazani, K., Beauchamp, R. L., Murthy, V., Bhide, P. G. and Ramesh, V. (2006), Alternative splicing in protein associated with Myc (Pam) influences its binding to c-Myc. J. Neurosci. Res., 83: 222–232. doi: 10.1002/jnr.20723
- Issue published online: 17 JAN 2006
- Article first published online: 8 DEC 2005
- Manuscript Accepted: 17 OCT 2005
- Manuscript Revised: 15 OCT 2005
- Manuscript Received: 18 AUG 2005
- National Institutes of Health. Grant Numbers: NS24279, NS41917
- tuberous sclerosis complex;
We recently identified Pam (for protein associated with c-Myc), as a binding partner for the tuberous sclerosis complex (TSC) protein tuberin in brain. The highly conserved Pam homologs in Drosophila and C. elegans are neuron-specific proteins that regulate synaptic growth. The Pam gene contains 83 exons and encodes a 4,641-amino-acid polypeptide with a predicted molecular weight of ∼510 kDa. In a previous study, we demonstrated that Pam is expressed as two forms, ∼450 kDa in rat embryonic and a ∼350 kDa in rat adult brain. Here we have extended that work to show the ∼450 kDa form is expressed in rat embryonic kidney, heart, and lung and in rat cell lines, and the ∼350 kDa form is expressed in adult rat tissues as well as in human and mouse brain and human and mouse cell lines. To understand the size difference, we investigated alternative splicing of Pam in brain and detected six isoforms in the Myc-binding region resulting from splicing of exon 53, and three new exons, 52A, 56, and 56A. We also demonstrate that the presence of exon 52A in Pam significantly enhances binding to Myc, suggesting functional importance of this alternative splicing. The presence of Pam in many cellular compartments, its spliced variants, as well as its multiple binding partners, including tuberin, make it a complex, yet intriguing protein in the nervous system. © 2005 Wiley-Liss, Inc.