. Author manuscript; available in PMC: 2010 Mar 1.

Published in final edited form as: Front Biosci. 2004 Sep 1;9:2556–2576. doi: 10.2741/1417

Table 1.

Summary of the functional role of HTLV-1 accessory proteins

Protein	pX ORF	Subcellular localization	In vitro functional activity	In vivo effects
p12^I	I	ER and cis-Golgi	Induces release of calcium from ER, interact with calcineurin as well as calreticulin and cause calcium- mediated NFAT activation; decreases IL-2 requirement for T-cell activation; enhances the production of IL-2; decreases MHC-1 surface expression	Abolished infectivity in rabbit model; reduced infectivity in nondividing primary human T-cells
p27^I	I	?	?	?, However, recognized by CTLs of infected subjects,
p30^II	II	Nucleus	Binds p300/CBP; differentially modulates HTLV-1 LTR mediated transcription; enhances transcription NFAT, NF-κB and AP-1 mediated transcription.	Reduced viral load in rabbit model^*
p13^II	II	Mitochondria and nucleus	Mitochondrial swelling and disruption of ? ?	Reduced viral load in rabbit model^*

Based on the reduced viral load from ACH.30/13 double-knockout proviral clone in rabbit model of infection (Bartoe et al, 2000)

? Function or expression unknown-predicted product.