TY - JOUR
T1 - Immunocytochemical evidence of Tulp1-dependent outer segment protein transport pathways in photoreceptor cells
AU - Grossman, Gregory H.
AU - Watson, Rao F.
AU - Pauer, Gayle J.T.
AU - Bollinger, Kathryn
AU - Hagstrom, Stephanie A.
N1 - Funding Information:
We thank Drs. W. Clay Smith, Andrew F.X. Goldberg, Roderick R. McInnes, Krzysztof Palczewski, Martin Biel and Rick H. Cote for their generous donations of antibodies and Dr. Neal S. Peachey for his insightful comments on this manuscript. Supported by NIH EY15638 (SAH) and EY16072 , Foundation Fighting Blindness (SAH), Hope for Vision (SAH), Prevent Blindness Ohio (RFW), Fight For Sight (GHG), Research to Prevent Blindness Center Grant , and a Research to Prevent Blindness Sybil B. Harrington Special Scholar Award (SAH).
PY - 2011/11
Y1 - 2011/11
N2 - Tulp1 is a protein of unknown function exclusive to rod and cone photoreceptor cells. Mutations in the gene cause autosomal recessive retinitis pigmentosa in humans and photoreceptor degeneration in mice. In tulp1-/- mice, rod and cone opsins are mislocalized, and rhodopsin-bearing extracellular vesicles accumulate around the inner segment, indicating that Tulp1 is involved in protein transport from the inner segment to the outer segment. To investigate this further, we sought to define which outer segment transport pathways are Tulp1-dependent. We used immunohistochemistry to examine the localization of outer segment proteins in tulp1-/- photoreceptors, prior to retinal degeneration. We also surveyed the condition of inner segment organelles and rhodopsin transport machinery proteins. Herein, we show that guanylate cyclase 1 and guanylate cyclase activating proteins 1 and 2 are mislocalized in the absence of Tulp1. Furthermore, arrestin does not translocate to the outer segment in response to light stimulation. Additionally, data from the tulp1-/- retina adds to the understanding of peripheral membrane protein transport, indicating that rhodopsin kinase and transducin do not co-transport in rhodopsin carrier vesicles and phosphodiesterase does not co-transport in guanylate cyclase carrier vesicles. These data implicate Tulp1 in the transport of selective integral membrane outer segment proteins and their associated proteins, specifically, the opsin and guanylate cyclase carrier pathways. The exact role of Tulp1 in outer segment protein transport remains elusive. However, without Tulp1, two rhodopsin transport machinery proteins exhibit abnormal distribution, Rab8 and Rab11, suggesting a role for Tulp1 in vesicular docking and fusion at the plasma membrane near the connecting cilium.
AB - Tulp1 is a protein of unknown function exclusive to rod and cone photoreceptor cells. Mutations in the gene cause autosomal recessive retinitis pigmentosa in humans and photoreceptor degeneration in mice. In tulp1-/- mice, rod and cone opsins are mislocalized, and rhodopsin-bearing extracellular vesicles accumulate around the inner segment, indicating that Tulp1 is involved in protein transport from the inner segment to the outer segment. To investigate this further, we sought to define which outer segment transport pathways are Tulp1-dependent. We used immunohistochemistry to examine the localization of outer segment proteins in tulp1-/- photoreceptors, prior to retinal degeneration. We also surveyed the condition of inner segment organelles and rhodopsin transport machinery proteins. Herein, we show that guanylate cyclase 1 and guanylate cyclase activating proteins 1 and 2 are mislocalized in the absence of Tulp1. Furthermore, arrestin does not translocate to the outer segment in response to light stimulation. Additionally, data from the tulp1-/- retina adds to the understanding of peripheral membrane protein transport, indicating that rhodopsin kinase and transducin do not co-transport in rhodopsin carrier vesicles and phosphodiesterase does not co-transport in guanylate cyclase carrier vesicles. These data implicate Tulp1 in the transport of selective integral membrane outer segment proteins and their associated proteins, specifically, the opsin and guanylate cyclase carrier pathways. The exact role of Tulp1 in outer segment protein transport remains elusive. However, without Tulp1, two rhodopsin transport machinery proteins exhibit abnormal distribution, Rab8 and Rab11, suggesting a role for Tulp1 in vesicular docking and fusion at the plasma membrane near the connecting cilium.
KW - Mouse mutant
KW - Photoreceptor
KW - Protein transport
KW - Retinal degeneration
KW - Retinitis pigmentosa
KW - Rhodopsin
KW - Tulp1
UR - http://www.scopus.com/inward/record.url?scp=81355146429&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=81355146429&partnerID=8YFLogxK
U2 - 10.1016/j.exer.2011.08.005
DO - 10.1016/j.exer.2011.08.005
M3 - Article
C2 - 21867699
AN - SCOPUS:81355146429
SN - 0014-4835
VL - 93
SP - 658
EP - 668
JO - Experimental eye research
JF - Experimental eye research
IS - 5
ER -