Post-translational modifications contribute to the observed molecular weight of Pyramus. (A) Supernatants from S2 cultured cells, immunoprecipitated with anti-HA, blotted with anti-HA. HA-Ths1-158 runs at the expected size of 20 kD, but HA-Pyr1-348 runs larger than predicted, at the same size as HA-Pyr1-466. (B) In vitro transcription/translation of HA-Pyr1-348 (left lane) and HA-Pyr1-466 (right lane) blotted with anti-HA, show HA-Pyr1-348 is likely post-translationally modified in vivo. (C) Schematic showing predicted events to explain the results in A and B: 1.) HA-Pyr1-348 and HA-Pyr1-466 are both translated to their predicted sizes as seen in vitro in (B). 2.) HA-Pyr1-348 and HA-Pyr1-466 are both modified post-translationally, likely by the addition of carbohydrate chains which increase their molecular weight to 50 kD and >50 kD (unobserved). 3.) HA-Pyr1-466 is probably subsequently cleaved to decrease its molecular weight to 50 kD. Small branching trees represent modifications and the inverse triangle represents a predicted cleavage site.
Tulin and Stathopoulos BMC Developmental Biology 2010 10:83 doi:10.1186/1471-213X-10-83